CN106400017A - Etching solution for etching multilayer thin film comprising copper layer and titanium layer etching method using said solution and substrate obtained by using said method - Google Patents

Abstract

Provided: an etchant for etching a multilayer thin film laminated on a substrate using at least one selected from glass, silicon dioxide, and silicon nitride, the multilayer thin film containing copper as a main component A copper layer and a titanium layer mainly composed of titanium; and an etching method of a multilayer thin film comprising the copper layer and the titanium layer using the same; and a substrate obtained by using the etching method. An etching solution, which is an aqueous solution comprising the following components and has a pH value of 1.5 to 2.5: (A) the concentration of hydrogen peroxide is 4.5 to 7.5% by mass; (B) the concentration of nitric acid is 0.8 to 6% by mass; (C ) concentration of fluorine compound is 0.2 to 0.5% by mass; (D) concentration of azoles is 0.14 to 0.3% by mass; (E) concentration of specific amine compound is 0.4 to 10% by mass; and (F) hydrogen peroxide is stable The concentration of the agent is 0.005 to 0.1% by mass.

Description

Etching solution, etching method using the same, and substrate obtained by using the etching method

technical field

This technology relates to: an etchant for etching a multilayer thin film comprising a copper layer mainly composed of copper and titanium mainly composed of titanium, laminated on a glass, silicon dioxide or silicon nitride substrate layer; and an etching method using the same. The etchant of the present invention is particularly suitable for etching a multilayer film with a copper layer on a titanium layer.

Background technique

Conventionally, aluminum or aluminum alloys have generally been used as wiring materials for display devices such as flat panel displays. However, with the increase in size and resolution of displays, such aluminum-based wiring materials have a problem of signal delay due to characteristics such as wiring resistance, and uniform screen display tends to become difficult.

Therefore, examples of using copper or metal wiring mainly composed of copper as a material with lower resistance are increasing. However, copper has the advantage of low resistance, but on the other hand, there are problems in that when copper is used for gate wiring, the adhesion between substrates such as glass and copper is not sufficient, and there are problems in the source/drain electrodes. When copper is used for electrode wiring, diffusion to the organic silicon semiconductor film which is the base may occur. In order to prevent such a problem, a barrier layer is laminated with a metal that has high adhesion to substrates such as glass and also has barrier properties that prevent diffusion into the organic silicon semiconductor film. As the metal, Titanium-based metals such as titanium and titanium nitride are often used.

However, a multilayer film mainly composed of copper or copper alloy is laminated on a substrate such as glass, silicon dioxide or silicon nitride (sometimes referred to as glass, etc.) The mask is etched in an etching process to form electrode patterns. Further, the method of this etching step includes a wet method (wet method) using an etchant and a dry method (dry method) using an etching gas such as plasma. Here, the etchant used in the wet (wet) method requires the following characteristics:

(i) High machining accuracy,

(ii) Less etching residue,

(ⅲ) less uneven etching,

(iv) The etching performance is stable against the dissolution of the wiring metal material including copper as the etching target,

And, in order to cope with the increase in size and resolution of displays, it is required that:

(v) A good wiring shape in which the wiring shape after etching is within a desired range is obtained.

More specifically, as shown in FIG. 1, the following features are strongly required: the angle (taper angle (5)) formed by the etched surface at the end of the copper wiring layer (2) and the underlying substrate (4) is 20° to 20°. 60° forward tapered shape; the distance from the end of the protective layer (1) to the end of the wiring layer (2) in contact with the protective layer (top CD loss (top CD loss), a×2) is 2.5 μm Below; the distance (bottom CD loss, b×2) from the end of the protective layer (1) to the end of the wiring layer (2) in contact with the barrier layer (3) provided under the wiring is 1.5 μm or less, and the barrier layer tailing (c×2) is 0.4 μm or less.

As an etchant used in the etching process of a laminated film containing copper or a copper alloy mainly composed of copper, for example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2002-302780) describes an etchant comprising: A neutral salt, at least one of an inorganic acid and an organic acid, hydrogen peroxide, and a hydrogen peroxide stabilizer.

Patent Document 2 (US Patent Application Publication No. 2003/0107023 Specification) proposes an etching solution containing hydrogen peroxide, an organic acid, and fluorine.

Patent Document 3 (International Publication No. 2011/021860) proposes an etchant containing hydrogen peroxide, fluorine, and an organic phosphine compound.

However, the etchant disclosed in Patent Documents 1 and 2 does not sufficiently satisfy the wiring shape after etching, and as a result, it may not be able to cope with an increase in size and resolution of a display. Furthermore, although Patent Document 2 contains acetic acid as an organic acid, it has a disadvantage that the dissolution of titanium is extremely slow (see Table 11 and Comparative Example 24).

In Patent Document 3, in order to etch molybdenum alloy and titanium, 0.01 to 1.0% by mass of a fluorine-containing compound is compounded, but fluorine corrodes glass, silicon dioxide or silicon nitride, which are often used as substrate bases, and as a result, changes in optical characteristics occur. etc. Therefore, an etchant with little damage to glass and the like is desired.

In addition, it is known in Patent Documents 1 to 3 that a relatively large amount of hydrogen peroxide is contained in the components (for example, 5.0 to 25% by mass in Patent Document 3), but it is dissolved in the etching solution due to repeated etching operations. The metal ions in the solution increase and the stability of hydrogen peroxide decreases. When the concentration of hydrogen peroxide in the etching solution decreases rapidly, desired etching performance cannot be obtained, and the replenishment amount of hydrogen peroxide increases, which is economically disadvantageous.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2002-302780

Patent Document 2: Specification of US Patent Application Publication No. 2003/0107023

Patent Document 3: International Publication No. 2011/021860

Contents of the invention

The problem to be solved by the invention

In the prior art, etchant containing hydrogen peroxide, acid, and fluorine compound is mostly used for etching multilayer thin films including copper layer and titanium layer, but fluorine compound will corrode substrates such as glass. Etching solutions containing fluorine compounds are strongly required to have an effect of not corroding substrates such as glass even if they contain fluorine compounds.

Furthermore, in order to control the etching rate of this etchant, pH adjustment is normally performed. Alkali components are used for pH adjustment, but when ammonia and potassium hydroxide are used, the corrosion of substrates such as glass is large, and it is difficult to efficiently and stably produce panels with target characteristics.

Quaternary ammonium hydroxide, which is another alkali component, is sometimes used for pH adjustment, but tetramethylammonium hydroxide is a toxic substance under the Prohibition of Toxic Substances Act, which is highly harmful to the human body and its use is restricted, so it is not preferable.

The present invention has been accomplished under such circumstances and provides: an etchant for etching a glass, silicon dioxide or silicon nitride substrate having a multilayer thin film comprising a copper layer mainly composed of copper and A titanium layer having titanium as a main component; and an etching method of a multilayer thin film comprising a copper layer and a titanium layer using the same; and a substrate obtained using the etching method. More specifically, there are provided: an etchant that significantly reduces corrosion of glass, silicon dioxide, or silicon nitride substrates although it is an etchant containing hydrogen peroxide and a fluorine compound; and a copper layer and a titanium layer using the same The etching method of the multi-layer film; and the substrate obtained by using the etching method.

solutions to problems

In order to achieve the aforementioned object, the inventors of the present application conducted intensive studies and found that although it is an etching solution containing a fluorine compound, by adding a specific amine compound to the etching solution, it is possible to treat the copper layer and the titanium layer. The wiring of the multilayer thin film is etched together, and at this time, the etching of the glass, silicon dioxide, or silicon nitride substrate is small, and the present invention has been completed.

More surprisingly, it was found that even if the amount of metal ions dissolved in the etching solution increases, the stability of hydrogen peroxide is not impaired, and high productivity is maintained by this etching method, and a good wiring shape is maintained after etching.

That is, the invention of the present application relates to the following technologies:

Wiring having a multilayer thin film comprising a copper layer and a titanium layer is etched by an etching solution, which is an aqueous solution having a pH of 1.5 to 2.5: containing (A) 4.5 to 7.5% by mass of hydrogen peroxide, (B ) 0.8-6% by mass of nitric acid, (C) 0.2-0.5% by mass of fluorine compounds, (D) 0.14-0.3% by mass of azoles, (E) 0.4-10% by mass of specific amine compounds, and (F) stable hydrogen peroxide 0.01 to 0.10% by mass of the agent, and the balance is composed of water.

[1] An etchant, which is an etchant for etching a multilayer thin film laminated on a substrate using at least one selected from glass, silicon dioxide, and silicon nitride, and the multilayer The thin film comprises a copper layer with copper as the main component and a titanium layer with titanium as the main component, and the etching solution is an aqueous solution containing the following components with a pH value of 1.5 to 2.5: (A) the concentration of hydrogen peroxide is 4.5 to 7.5 mass%, (B) nitric acid concentration of 0.8 to 6 mass%, (C) fluorine compound concentration of 0.2 to 0.5 mass%, (D) azole concentration of 0.14 to 0.3 mass%, (E) amine compound The concentration is 0.4-10% by mass and the concentration of the (F) hydrogen peroxide stabilizer is 0.005-0.1% by mass. The aforementioned (E) amine compound is preferably selected from alkylamines (E1) having one or more linear or branched C2-5 alkyl groups optionally substituted by methoxy groups, and having one or more Alkanolamines having two straight-chain or branched hydroxyalkyl groups with 2 to 5 carbons, and optionally having one or two straight-chain or branched alkyl groups with 2 to 5 carbons ( One or more of E2), diamine (E3) having a linear or branched C2-5 alkylene group, and cyclohexylamine (E4). Here, "containing copper as a main component" means that copper is contained in an amount of at least 50% by mass, preferably at least 60% by mass, and more preferably at least 70% by mass. "Having titanium as a main component" means that titanium is contained at least 50% by mass, preferably at least 60% by mass, more preferably at least 70% by mass.

[2] The etching solution according to item 1, wherein the (C) fluorine compound is at least one selected from hydrofluoric acid, ammonium fluoride, and ammonium acid fluoride.

[3] The etching solution according to item 1, wherein the (D) azole is 5-amino-1H-tetrazole.

[4] The etching solution according to item 1, wherein the (E) amine compound is selected from linear or branched alkyl groups having 1 to 6 carbon atoms (wherein chains other than cyclic hexyl groups are excluded). One or more of alkylamines, alkanolamines, diamines and cyclic amines.

[5] The etching solution according to Item 1 or Item 4, wherein (E) the amine compound is selected from isopropanolamine, 3-amino-1-propanol, N-butylethanolamine, N,N -Dimethylamino-2-propanol, 2-methoxyethylamine, cyclohexylamine, n-butylamine, dibutylamine, tert-butylamine, N-methyl-n-butylamine, 1,4-diaminobutane , 2-amino-1-butanol, 5-amino-1-pentanol, 3-methoxypropylamine, 2-dimethylaminoethanol and 2-aminoethanol at least one.

[6] The etching solution according to item 1, wherein (F) the hydrogen peroxide stabilizer is at least one selected from phenylurea and phenolsulfonic acid.

[7] The etching solution according to item 1, wherein the top CD loss is 2.5 μm or less, the bottom CD loss is 1.5 μm or less, and the tailing is 0.4 μm or less.

[8] The etchant according to item 1, wherein the etching rate of glass is 60 nm/min or less.

[9] The etchant according to item 1, wherein the etching rate of silicon dioxide and silicon nitride is /min or less.

[10] The etching solution according to item 1, wherein an appropriate etching time for the multilayer thin film including a copper layer mainly composed of copper and a titanium layer mainly composed of titanium is 80 seconds to 140 seconds.

[11] The etching solution according to item 1, wherein the stability of hydrogen peroxide in the etching solution when 4000 ppm of copper and 360 ppm of titanium are added to the etching solution and stored at 50° C. for 2 hours is 0.075% / hour or less.

[12] The etchant according to item 1, wherein the multilayer thin film laminated on the substrate using one or more selected from glass, silicon dioxide, and silicon nitride is made of titanium containing titanium as a main component. Copper layers with copper as the main component are laminated on top of each other.

[13] A method for etching a multilayer thin film comprising a copper layer mainly composed of copper and a titanium layer mainly composed of titanium, wherein the multilayer thin film laminated on a substrate is combined with the first to the first The etchant contact according to any one of item 12, the substrate uses one or more selected from glass, silicon dioxide, and silicon nitride, and the multilayer film includes a copper layer with copper as the main component and A titanium layer in which titanium is the main component.

The effect of the invention

According to a preferred aspect of the present invention, by using the etching solution of the present invention in the etching process of a multilayer film laminated on a glass, silicon dioxide or silicon nitride (sometimes referred to as glass, etc.) substrate, the bath of the etching solution Long life (bathlife), high processing accuracy, less etching residue, unevenness, and a good wiring shape after etching can be provided, thereby providing substrates such as glass that can cope with the increase in size and resolution of displays. Among them, the The multilayer thin film includes a copper layer mainly composed of copper and a titanium layer mainly composed of titanium.

Description of drawings

Fig. 1 is a schematic diagram of a cross-section of a wiring having a multilayer film laminated on a glass, silicon dioxide or silicon nitride substrate, the multilayer film including a copper layer mainly composed of copper when etching is performed using the etching solution of the present invention and a titanium layer mainly composed of titanium.

Explanation of reference signs

1. Protective layer

2. Wiring layer

3. Barrier layer

4. Substrate

5. Cone angle

a: Top CD loss (a)

b: Bottom CD loss (b)

c: trailing (c)

detailed description

For etching multilayer thin films consisting of copper and titanium layers laminated on glass, silicon dioxide or silicon nitride substrates etchant

The etching solution of the present invention is characterized in that it is used for etching a multilayer film comprising a copper layer and a titanium layer laminated on a glass substrate, and the etching solution is an aqueous solution as follows and has a pH value of 1.5 to 2.5:

Contains (A) hydrogen peroxide at a concentration of 4.5 to 7.5% by mass, (B) nitric acid at a concentration of 0.8 to 6.0% by mass, (C) a fluorine compound at a concentration of 0.2 to 0.5% by mass, and (D) an azole concentration 0.14 to 0.30% by mass, the concentration of (E) amine compound is 0.4 to 10% by mass, the concentration of (F) hydrogen peroxide stabilizer is 0.005 to 0.1% by mass, and the balance is composed of water.

(A) hydrogen peroxide

The hydrogen peroxide used in the etching solution of the present invention has the function of oxidizing copper metal as an oxidizing agent, and the content in the etching solution is preferably 4.5% by mass or more, more preferably 5.0% by mass or more, and preferably 7.5% by mass or less , more preferably 7.0% by mass or less, still more preferably 6.5% by mass or less. Among them, the content of hydrogen peroxide in the etching solution of the present invention is preferably 4.5 to 7.5% by mass, more preferably 4.5 to 7.0% by mass, and particularly preferably 5.0 to 6.5% by mass. When the content of hydrogen peroxide is within the above range, an appropriate etching rate can be secured, the control of the amount of etching becomes easy, and localized corrosion of copper wiring does not occur, which is preferable.

(B) nitric acid

The nitric acid used in the etching solution of the present invention promotes the dissolution of copper oxidized by (A) hydrogen peroxide, and the content of the nitric acid in the etching solution is preferably 0.8 to 6% by mass, more preferably 2 to 6% by mass, especially Preferably it is 3.5-6 mass %. If the content of nitric acid is within the above range, an appropriate etching rate can be obtained, and a good wiring shape after etching can be obtained.

(C) Fluorine compounds

The fluorine compound used in the etching solution of the present invention contributes to the etching of the barrier layer formed by titanium-based metals, and the content in the etching solution is preferably 0.2 to 0.5% by mass, more preferably 0.2 to 0.4% by mass, particularly preferably 0.2 to 0.3% by mass. When the content of the fluorine compound is within the above range, a favorable etching rate of the barrier layer made of titanium-based metal can be obtained.

The fluorine compound is not particularly limited as long as it generates fluoride ions in the etchant, and preferred examples include hydrofluoric acid, ammonium fluoride, and ammonium acid fluoride, which can be used alone or in combination. Among these, ammonium fluoride and ammonium acid fluoride are more preferable from the viewpoint of low toxicity.

(D) Azole

Examples of azoles used in the etching solution of the present invention preferably include: 1,2,4-triazole, 1H-benzotriazole, 5-methyl-1H-benzotriazole, 3-amino-1H -Triazoles such as triazole, 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole and other tetrazoles, 1,3- Thiazoles such as thiazole and 4-methylthiazole, and the like. Among them, tetrazoles are preferable, and 5-amino-1H-tetrazole is especially preferable.

The content of azoles in the etching solution is preferably at least 0.14% by mass, more preferably at least 0.15% by mass, and is preferably at most 0.3% by mass, more preferably at most 0.25% by mass. Among them, the content of the azoles in the etching solution of the present invention is preferably 0.14 to 0.3% by mass, particularly preferably 0.15 to 0.25% by mass. If the content of the azoles is within the above range, the etching rate of copper wiring can be appropriately controlled, and a favorable wiring shape after etching can be obtained.

(E) Amine compound

It is considered that the amine compound used in the etching solution of the present invention has a function of reducing corrosion of substrates using glass, silicon dioxide, or silicon nitride due to fluorine compounds. As an amine compound effectively having these functions, preferably, those having a linear, branched, or cyclic C1-6 alkyl group (among them, chain hexyl groups other than cyclic hexyl groups are excluded) Alkylamines, alkanolamines, diamines and cyclic amines. Amines having an alkyl group having 7 or more carbon atoms have low solubility in water, so they are difficult to dissolve in an etching solution, and even if they can be partially dissolved, obvious foaming occurs, making it difficult to be practical as an etching solution.

As the amine compound used in the etching solution of the present invention, there may be mentioned: alkylamine (E1 ); having 1 or 2 linear or branched hydroxyalkyl groups with 2 to 5 carbons, and optionally having 1 or 2 linear or branched alkyl groups with 2 to 5 carbons alkanolamine (E2); diamine (E3) having a linear or branched C2-5 alkylene group; and cyclohexylamine (E4). Hereinafter, each amine compound will be described.

＜Alkylamine (E1)＞

Alkylamines (E1) can be represented by the following formula:

[wherein, R ¹ is a linear or branched alkyl group with 2 to 5 carbon atoms optionally substituted by methoxy, and m is 1, 2 or 3. ].

Specifically, examples of alkylamines (E1) include ethylamine, 2-methoxyethylamine, n-propylamine, isopropylamine, 3-methoxypropylamine, n-butylamine, sec-butylamine, and isobutylamine. , tert-butylamine, pentylamine, 2-aminopentane, 3-aminopentane, 1-amino-2-methylbutane, 2-amino-2-methylbutane, 3-amino-2-methylbutane , 4-amino-2-methylbutane, 5-amino-2-methylpentane and other primary alkylamines; dipropylamine, diisopropylamine, dibutylamine, di-sec-butylamine, di-tert-butylamine, diamylamine, Ethylamine, methylpropylamine, methylisopropylamine, methylbutylamine, methylisobutylamine, methyl-sec-butylamine, methyl-tert-butylamine, methylpentylamine, methylisoamylamine, ethylpropylamine , ethylisopropylamine, ethylbutylamine, ethylisobutylamine, ethyl-sec-butylamine, ethylpentylamine, ethylisoamylamine, propylbutylamine, propylisobutylamine and other secondary alkylamines; Tertiary alkylamines such as trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, dimethylethylamine, methyldiethylamine, methyldipropylamine, etc.

＜Alkanolamine (E2)＞

Alkanolamines (E2) can be represented by the following formula:

[wherein, R ² OH is a linear or branched hydroxyalkyl group with 2 to 5 carbons, R ³ is a linear or branched alkyl group with 2 to 5 carbons, and p is 1 or 2, q is 0, 1 or 2, and p+q is 1, 2 or 3. ].

Specifically, examples of the alkanolamine (E2) include ethanolamine, N-methylethanolamine, N,N-dimethylethanolamine, N-ethylethanolamine, N,N-diethylethanolamine, N - Propanolamine, N-propylethanolamine, N-butylethanolamine, diethanolamine, isopropanolamine, N-methylisopropanolamine, N-ethylisopropanolamine, N-propylisopropanolamine Amine, 2-amino-1-propanol, 3-amino-1-propanol, N-methyl-2-amino-1-propanol, N,N-dimethylamino-2-propanol, N- Ethyl-2-amino-1-propanol, 1-amino-2-butanol, N-methyl-1-amino-2-butanol, N-ethyl-1-amino-2-butanol, 2 -amino-1-butanol, N-methyl-2-amino-1-butanol, N-ethyl-2-amino-1-butanol, 3-amino-1-butanol, N-ethyl- 3-amino-1-butanol, 1-amino-4-butanol, 1-amino-2-methyl-2-propanol, 2-amino-2-methyl-1-propanol, 1-amino- 4-pentanol, 2-amino-4-methyl-1-pentanol, 5-amino-1-pentanol, 1-aminopropane-2,3-diol, 2-aminopropane-1,3-diol alcohol, tris(oxymethyl)aminomethane and 1,2-diamino-2-propanol, etc. It is not limited to these. Moreover, in this invention, these can be used individually or in combination of multiple types.

Examples of the diamine (E3) include: ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, diethyl-1,3-propylenediamine, 1,4-diaminobutyl alkanes, 1,3-diaminobutane, 2,3-diaminobutane, pentamethylenediamine, 2,4-diaminopentane, etc.

Moreover, cyclohexylamine (E4) is mentioned as an amine compound.

In the present invention, these amine compounds can be used alone or in combination.

Among these amine compounds, preferably, isopropanolamine, 3-amino-1-propanol, N-butylethanolamine, N,N-dimethylamino-2-propanol, 2-methoxyethyl Amine, cyclohexylamine, n-butylamine, dibutylamine, tert-butylamine, N-methyl-n-butylamine, 1,4-diaminobutane, 2-amino-1-butanol, 5-amino-1-pentane Alcohol, 3-methoxypropylamine, 2-dimethylaminoethanol, 2-aminoethanol, particularly preferably 3-methoxypropylamine, N-methyl-n-butylamine, n-butylamine, 2-amino-1 -Butanol, cyclohexylamine, N-butylethanolamine, 5-amino-1-pentanol.

The content of the amine compound in the etching solution is preferably at least 0.4% by mass, more preferably at least 1% by mass, still more preferably at least 2% by mass, and preferably at most 10% by mass, more preferably at most 9% by mass, even more preferably It is 8 mass % or less. Among them, the content of the amine compound in the etching solution is preferably 0.4 to 10% by mass, more preferably 1 to 9% by mass, still more preferably 1 to 8% by mass, particularly preferably 2 to 8% by mass. If the content of the amine compound is within the above range, even if the metal concentration in the liquid increases, the decomposition of hydrogen peroxide will be slow, and an etching liquid with little damage to the glass substrate can be obtained.

(F) Hydrogen peroxide stabilizer

The etching solution of the present invention preferably contains a hydrogen peroxide stabilizer. As the hydrogen peroxide stabilizer, any substance that is generally used as a hydrogen peroxide stabilizer can be used without limitation, except for urea-based compounds such as phenylurea, allylurea, 1,3-dimethylurea, and thiourea. In addition to the hydrogen peroxide stabilizer, preferable examples include phenylacetamide, phenylethylene glycol, phenolsulfonic acid, and the like, and phenylurea and phenolsulfonic acid are particularly preferable. Moreover, in this invention, these can be used individually or in combination of multiple types.

The content of the hydrogen peroxide stabilizer in the etching solution of the present invention is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and preferably 0.1% by mass or less, more preferably It is 0.09 mass % or less, More preferably, it is 0.08 mass % or less. Among them, the content of the hydrogen peroxide stabilizer in the etching solution of the present invention is preferably 0.005 to 0.1% by mass, particularly preferably 0.01 to 0.09% by mass, particularly preferably 0.01 to 0.08% by mass.

pH value

The etchant of the present invention requires a pH in the range of 1.5 to 2.5. When the pH value is less than 1.5, the etching rate becomes too high, so that localized corrosion of copper wiring occurs, and etching unevenness (unevenness) may occur in copper wiring. In addition, when the pH value exceeds 2.5, the stability of hydrogen peroxide decreases, heat generation and decomposition occur, and the concentration of hydrogen peroxide decreases. As a result, the etching rate of copper wiring decreases, and stable production may be caused.

The pH adjustment is usually performed by adding (E) an amine compound, but other pH adjusters may be added as long as the effects of the present invention are not impaired. For example, generally used inorganic acids, organic acids, inorganic bases, organic bases and the like can be used.

water

Using water as a diluent, the water of the present invention is preferably water obtained by removing metal ions, organic impurities, particulate particles, etc. through distillation, ion exchange treatment, filtration treatment, various adsorption treatments, etc., particularly preferably pure water or ultrapure water .

other ingredients

In addition to the components (A) to (F) above, the etching solution of the present invention may contain various additives, surfactants, colorants, defoamers, etc. that are generally used in etching solutions within the range that does not hinder the effect of the etching solution.

Method for etching multilayer thin film comprising copper layer and titanium layer laminated on glass, silicon dioxide or silicon nitride substrate

The etching method of the present invention is a method of etching a multilayer thin film including a copper layer and a titanium layer laminated on a glass substrate, the method is characterized in that the etching liquid of the present invention is used, and the method comprises the steps of making the object to be etched and the The process of contacting the etching solution of the present invention, wherein the etching solution of the present invention comprises (A) a concentration of hydrogen peroxide of 4.5 to 7.5% by mass, (B) a concentration of nitric acid of 0.8 to 6% by mass, (C) fluorine The concentration of the compound is 0.2 to 0.5% by mass, the concentration of (D) azoles is 0.14 to 0.3% by mass, the concentration of (E) amine compound is 0.4 to 10% by mass and the concentration of (F) hydrogen peroxide stabilizer is 0.005 An aqueous solution comprising -0.1% by mass, the balance being water, and an etching solution having a pH of 1.5-2.5.

There is no particular limitation on the method of contacting the etching object with the etching solution. For example, the method of contacting the etching solution with the object by dripping (single-chip rotation processing), spraying, etc.; the method of immersing the object in the etching solution Methods such as wet (wet) etching methods. In the present invention, it is preferable to employ a method of immersing an object in an etching solution, or spraying and bringing it into contact.

The use temperature of the etching solution is preferably 10 to 70°C, particularly preferably 20 to 50°C. If the temperature of the etchant is 10° C. or higher, the etching rate will not become too slow, so the production efficiency will not be significantly lowered. On the other hand, if the temperature is 70° C. or lower, changes in the liquid composition can be suppressed, and the etching conditions can be kept constant. By increasing the temperature of the etchant, the etching rate increases, but an optimum treatment temperature may be appropriately determined in consideration of suppressing small changes in the composition of the etchant.

In addition, according to the etching method of the present invention, the multilayer thin film including the copper layer and the titanium layer laminated on the glass substrate can be etched together, and after etching, a good wiring shape as shown in FIG. 1 can be obtained.

In the etching method of the present invention, the object to be etched by the etchant is: for example, a barrier layer (titanium layer) formed of titanium or a titanium-based material mainly composed of titanium is sequentially laminated on a substrate such as glass as shown in FIG. A protective layer is further coated on a multilayer film including a copper layer and a titanium layer formed of metal wiring formed of copper or a copper-based material (copper layer), and the desired pattern mask is exposed and transferred. Development is performed to form a desired resist pattern, thereby forming an object to be etched. Here, in the present invention, the multilayer thin film including a copper layer and a titanium layer is represented by a configuration in which a copper layer is present on a titanium layer as shown in FIG. 1 , and also includes a three-layer structure in which a titanium layer is further present on a copper layer. scheme.

In the etching method of the present invention, as shown in FIG. 1, an etching object having a copper layer mainly composed of copper on a titanium layer mainly composed of titanium is from the viewpoint of effectively exhibiting the performance of the etching solution of the present invention. Departure is preferred. In addition, such a multilayer film comprising a copper layer mainly composed of copper and a titanium layer mainly composed of titanium is preferably used for wiring in display devices such as flat panel displays. Therefore, the object to be etched in which the copper layer exists on the titanium layer is also a preferable aspect from the viewpoint of the field of use.

The copper wiring is not particularly limited as long as it is laminated with copper or a material mainly composed of copper. Examples of the titanium-based material for laminating the barrier layer include titanium and titanium nitride, which is its nitride, and are not limited to these titanium compounds.

The thickness of the multilayer thin film which is the object to be etched in the present invention is usually 20 nm to 1500 nm, preferably 50 nm to 1200 nm, more preferably 100 nm to 1000 nm, and still more preferably 150 nm to 800 nm.

In the etching method of the present invention, the concentrations of (A) hydrogen peroxide and (B) nitric acid contained in the etching solution are respectively consumed as oxidizing agents for copper wiring as described above, and (B) nitric acid is It is also consumed in the dissolution, and therefore, the reduction in etching performance may occur due to the reduction in the concentration of (A) hydrogen peroxide and (B) nitric acid in the etching solution used. In such a case, by appropriately adding (A) hydrogen peroxide and (B) nitric acid simultaneously or separately, the bath life can be prolonged and used.

Example

Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Fabrication example of multilayer thin film including copper layer and titanium layer

Titanium was sputtered to a thickness of 25 nm on a glass substrate, and then copper was sputtered to a thickness of 400 nm to laminate a copper layer of a wiring material. Next, a protective layer is applied, exposure transfer is performed on a pattern mask, and development is performed to form a wiring pattern, thereby producing a multilayer film including a copper layer and a titanium layer on a glass substrate.

Etching method and just etching time (JET) for copper and titanium layers

Using the etching solution described in Tables 1 to 6 and Tables 10 and 11, the glass substrate on which the copper layer and the titanium layer were laminated was immersed for 150 seconds at 35° C., washed with water, and dried with nitrogen gas.

The time until the etching by visual observation reached the glass substrate was made into appropriate etching time, and it judged by the following reference|standard.

determination:

E: 90 seconds to 120 seconds

G: More than 80 seconds to less than 90 seconds, more than 120 seconds to 140 seconds

B: less than 80 seconds, more than 140 seconds

Set E and G as pass.

Cross-sectional observation of etched multilayer films containing copper and titanium layers

Cut the multilayer thin film sample obtained by the above-mentioned etching method including the copper layer and the titanium layer, and use a scanning electron microscope (model: S5000H type manufactured by Hitachi, Ltd.) to examine at a magnification of 50000 times (accelerating voltage 2kV, accelerating current 10μA) ) to observe the section.

Based on the obtained SEM images, the cone angle (5), top CD loss (a), bottom CD loss (b) and tailing (c) shown in Figure 1 were determined.

The shape after etching was judged by the following criteria using taper angle (°), top CD loss (μm), bottom CD loss (μm), and smear (μm).

determination:

The top CD loss (=a×2) is 2.5μm or less as acceptable

Bottom CD loss (=b×2) of 1.5 μm or less is acceptable

Tailing (=c×2) of 0.4 μm or less is acceptable

A taper angle of 20° to 60° was considered acceptable.

Examples of fabrication of glass, silicon dioxide, or silicon nitride substrates for corrosion evaluation

Coating a protective layer on a glass, silicon dioxide or silicon nitride substrate, exposing and transferring to a pattern mask, and then developing to form a wiring pattern is used as a substrate for evaluation.

Evaluation of Corrosion to Glass Substrates

The glass substrate for corrosion evaluation obtained above was immersed in the etchant described in Table 6, 10, and 11 for 20 minutes, washed with water, and dried using nitrogen gas.

The height difference between the corroded part and the non-corroded part was measured using a contact roughness meter (Contourecord 2700SD3, manufactured by Tokyo Seiki Co., Ltd.), the corrosion rate was calculated, and evaluation was performed according to the following criteria. The results are shown in Tables 7, 12 and 13.

determination:

E: below 50nm/min

G: more than 50nm/min to less than 60nm/min

B: More than 60nm/min

Set E and G as pass.

Evaluation of corrosion on silicon dioxide or silicon nitride substrates

The silicon dioxide or silicon nitride substrates for corrosion evaluation obtained above were immersed in the etching solutions described in Tables 6, 10, and 11 for 5 minutes, washed with water, and dried with nitrogen gas.

The cross sections of the corroded part and the non-corroded part were observed with a scanning electron microscope (model: S5000H, manufactured by Hitachi, Ltd.) at a magnification of 50000 times (accelerating voltage 2 kV, accelerating current 10 μA). Based on the obtained SEM image, the corrosion rate was calculated and evaluated according to the following criteria. The results are shown in Tables 8, 9 and 14-17.

determination:

E: the following

G: more than the following

B: more than

Set E and G as pass.

Evaluation of Hydrogen Peroxide Stability

The hydrogen peroxide concentration was measured before and after storage when the etching solution in which 4000 ppm of copper and 360 ppm of titanium were dissolved was stored in a 50° C. water bath for 2 hours, and the decomposition rate of hydrogen peroxide was obtained. The analysis of the concentration of hydrogen peroxide was carried out by redox titration using potassium permanganate. The hydrogen peroxide decomposition rate was calculated|required by the following formula, and it evaluated according to the following judgment criteria. The results are shown in Tables 6, 10, and 11.

Hydrogen peroxide decomposition rate (%/hour) = (hydrogen peroxide concentration before storage - hydrogen peroxide concentration after storage) / storage time

determination:

E: 0.050%/hour or less

G: more than 0.050%/hour to less than 0.075%/hour

B: over 0.075%/hour

Set E and G as pass.

Examples 1-10

Added 5.88% by mass of hydrogen peroxide, 4.12% by mass of nitric acid, 0.25% by mass of acid ammonium fluoride, 0.21% by mass of 5-amino-1H-tetrazole, 0.03% by mass of phenylurea and water, with pH value becomes 1.5～2.5, add 2-aminoethanol (Example 1), 2-dimethylaminoethanol (Example 2), 3-methoxypropylamine (Example 3), N-Butylamine (Example 4), N-Methyl-n-Butylamine (Example 5), Isopropanolamine (Example 6), 3-amino-1-propanol (Example 7), N-Butylamine Ethanolamine (Example 8), N,N-Dimethylamino-2-propanol (Example 9) and 2-methoxyethylamine (Example 10).

The above-obtained glass substrate having a multilayer thin film comprising a copper layer and a titanium layer was immersed in the above etching solution at 35° C. for 150 seconds for etching to obtain an etched multilayer thin film sample comprising a copper layer and a titanium layer. For the obtained sample, the cone angle (°), top CD loss (a, μm), bottom CD loss (b, μm) and tailing (c, μm) were obtained by observing the above-mentioned electron microscope, and the results are described in the table 1 and Table 2.

It can be seen that the etching liquids of Examples 1 to 10 are etching liquids capable of etching with excellent etching shapes.

Comparative Examples 1-10

In Example 4, the concentration of hydrogen peroxide was set to 3.0% by mass (Comparative Example 1) and 9.0% by mass (Comparative Example 2), and the concentration of nitric acid was set to 0.70% by mass (Comparative Example 3) and 9.00% by mass (Comparative Example 3). 4), 5-amino-1H-tetrazole was set to 0.08% by mass (Comparative Example 5) and 0.60% by mass (Comparative Example 6), and the concentration of the amine compound (n-butylamine) was set to 0.20% by mass (Comparative Example 7) and 11.0% by mass (Comparative Example 8) and 0.08% by mass (Comparative Example 9) and 0.80% by mass (Comparative Example 10) of acidic ammonium fluoride resulted in problems such as inability to measure the etched shape or loss of wiring. The results are summarized in Table 3 and Table 4.

Comparative Examples 11-15

An etching solution was prepared in the same manner as in Example 1, except that the amine compound (Comparative Example 15) was not added, and hexylamine (Comparative Example 11) and diethylenetriamine (Comparative Example 15) were added so that the pH value became 1.5 to 2.5. 12), 2-(1-piperazinyl) ethylamine (comparative example 13) or triethanolamine (comparative example 14), so although etching was carried out, the desired etched shape could not be obtained due to the generation of tailing (Table 5 ).

[Table 1]

※1 Mitsubishi Gas Chemical Co., Ltd. product

※2 Manufactured by Wako Pure Chemical Industries, Ltd.

※3 Acid ammonium fluoride, manufactured by STELLA CHEMIFA CORPORATION

※4 5-Amino-1H-tetrazole, manufactured by Wako Pure Chemical Industries, Ltd.

※5 amine compounds:

Example 1: 2-Aminoethanol (manufactured by Wako Pure Chemical Industries, Ltd.)

Example 2: 2-Dimethylaminoethanol (manufactured by Wako Pure Chemical Industries, Ltd.)

Example 3: 3-methoxypropylamine (manufactured by Wako Pure Chemical Industries, Ltd.)

Example 4: n-Butylamine (manufactured by Wako Pure Chemical Industries, Ltd.)

Example 5: N-methyl-n-butylamine (manufactured by Wako Pure Chemical Industries, Ltd.)

※6 Phenylurea, manufactured by Wako Pure Chemical Industries, Ltd.

[Table 2]

※1 Mitsubishi Gas Chemical Co., Ltd. product

※2 Manufactured by Wako Pure Chemical Industries, Ltd.

※3 Acid ammonium fluoride, manufactured by STELLA CHEMIFA CORPORATION

※4 5-Amino-1H-tetrazole, manufactured by Wako Pure Chemical Industries, Ltd.

※5 amine compounds:

Example 6: Isopropanolamine (manufactured by Wako Pure Chemical Industries, Ltd.)

Example 7: 3-Amino-1-propanol (manufactured by Wako Pure Chemical Industries, Ltd.)

Example 8: N-butylethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.)

Example 9: N,N-Dimethylamino-2-propanol (manufactured by Wako Pure Chemical Industries, Ltd.)

Example 10: 2-methoxyethylamine (manufactured by Wako Pure Chemical Industries, Ltd.)

※6 Phenylurea, manufactured by Wako Pure Chemical Industries, Ltd.

[table 3]

※1 Mitsubishi Gas Chemical Co., Ltd. product

※2 Manufactured by Wako Pure Chemical Industries, Ltd.

※3 Acid ammonium fluoride, manufactured by STELLA CHEMIFA CORPORATION

※4 5-Amino-1H-tetrazole, manufactured by Wako Pure Chemical Industries, Ltd.

※5 n-butylamine, manufactured by Wako Pure Chemical Industries, Ltd.

※6 Phenylurea, manufactured by Wako Pure Chemical Industries, Ltd.

[Table 4]

※1 Mitsubishi Gas Chemical Co., Ltd. product

※2 Manufactured by Wako Pure Chemical Industries, Ltd.

※3 Acid ammonium fluoride, manufactured by STELLA CHEMIFA CORPORATION

*4 5-Amino-1H-tetrazole, manufactured by Wako Pure Chemical Industries, Ltd.

※5 n-butylamine, manufactured by Wako Pure Chemical Industries, Ltd.

※6 Phenylurea, manufactured by Wako Pure Chemical Industries, Ltd.

[table 5]

※1 Mitsubishi Gas Chemical Co., Ltd. product

※2 Manufactured by Wako Pure Chemical Industries, Ltd.

※3 Fluoride ion supply source:

Comparative Examples 11 to 13: Acid ammonium fluoride, manufactured by STELLA CHEMIFA CORPORATION

Comparative Example 14: Ammonium fluoride, manufactured by Wako Pure Chemical Industries, Ltd.

※4 5-Amino-1H-tetrazole, manufactured by Wako Pure Chemical Industries, Ltd.

※5 alkali component compounds:

Comparative Example 11: Hexylamine, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Example 12: Diethylenetriamine, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Example 13: 2-(1-piperazinyl)ethylamine, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Example 14: Triethanolamine, manufactured by Wako Pure Chemical Industries, Ltd.

※6 Phenylurea, manufactured by Wako Pure Chemical Industries, Ltd.

Examples using the etchant of the present invention can perform etching within the target time, and the wiring shapes after etching are all good (Tables 1 and 2).

On the other hand, in Comparative Example 1 in which the concentration of hydrogen peroxide was lower than the desired concentration range, the etching could not be performed within a predetermined time because the etching rate was insufficient. In addition, in Comparative Example 2 in which the concentration of hydrogen peroxide exceeded the desired concentration range, the etching rate became too fast and the CD loss became too large. In Comparative Example 3 in which the concentration of nitric acid was lower than the desired concentration range, etching could not be performed within a predetermined time because the etching rate was insufficient. In Comparative Example 4 in which the concentration of nitric acid exceeded the desired concentration range, the etching rate became too high, and no wiring remained on the substrate after etching for a predetermined time. In Comparative Example 5 in which the azole concentration was lower than the desired concentration range, the etching rate became too fast and the CD loss became too large (above, Table 3).

In Comparative Example 6 in which the concentration of azoles exceeded the desired concentration range, etching could not be performed within a predetermined time due to insufficient etching rate. In Comparative Example 7 in which the concentration of the amine compound was lower than the desired concentration range, the etching rate became too fast, and wiring did not remain on the substrate after etching for a predetermined time. In Comparative Example 8 in which the concentration of the amine compound exceeded the desired concentration range, the etching could not be performed within a predetermined time because the etching rate was insufficient. In Comparative Example 9 in which the concentration of the fluorine compound was lower than the desired concentration range, the etching rate was insufficient, etching residue (smearing) of the titanium layer occurred, and the wiring shape could not be measured. In Comparative Example 10 in which the concentration of the fluorine compound exceeded the desired concentration range, the etching rate of the titanium layer was too high, resulting in voids in the wiring, and the desired cross-sectional shape could not be obtained (above, Table 4).

In Comparative Examples 11 to 14 using an amine compound other than the amine compound of the present invention, the tailing phenomenon of the titanium layer due to the etching delay of the titanium layer occurred, and a desired cross-sectional shape could not be obtained. In Comparative Example 15 in which no amine compound was used, the etching rate was too high, and wiring did not remain on the substrate after etching for a predetermined time (above, Table 5).

Examples 11-15

Added 5.46% by mass of hydrogen peroxide, 4.66% by mass of nitric acid, 0.34% by mass of acid ammonium fluoride, 0.21% by mass of 5-amino-1H-tetrazole, 0.03% by mass of phenylurea and water, with pH value becomes the mode of 1.5～2.5, add as amine compound 3-methoxypropylamine (embodiment 11), methylbutylamine (embodiment 12), 2-amino-1-butan-1-alcohol ( Example 13), n-butylamine (Example 14), cyclohexylamine (Example 15). Then, except adding 4000 ppm of copper powder and 360 ppm of titanium powder to this liquid, the same test as Example 1 was performed, and the same evaluation as Example 1 was implemented, and the evaluation test of hydrogen peroxide stability was performed. The obtained results are summarized in Table 6.

Examples 16-30

The substrates for corrosion evaluation of glass, silicon dioxide, and silicon nitride were immersed in the same etchant as in Examples 11 to 15, respectively, and etched, and the corrosivity of the obtained samples to each substrate material was evaluated. The obtained results are summarized in Tables 7-9.

Comparative Examples 16, 17, 19-22

Added 5.46% by mass of hydrogen peroxide, 4.66% by mass of nitric acid, 0.34% by mass of acid ammonium fluoride, 0.21% by mass of 5-amino-1H-tetrazole, 0.03% by mass of phenylurea and water, with pH becomes 1.5 to 2.5, adding potassium hydroxide (comparative example 16), ammonia (comparative example 17), diethylenetriamine (comparative example 19), 2-(2-aminoethane) as alkali components Oxygen) ethanol (comparative example 20), dimethylamine (comparative example 21), piperazine (comparative example 22), add copper powder 4000ppm and titanium powder 360ppm in the obtained liquid, carry out the test similar to embodiment 11～15 . The obtained results are summarized in Table 10 and Table 11.

Comparative Example 18

The nitric acid in Comparative Example 16 was replaced by 5.06% by mass of sulfuric acid, n-butylamine was added so that the pH value became 1.5 to 2.5, 4000 ppm of copper powder and 360 ppm of titanium powder were added to the obtained liquid, and the same test as in Comparative Example 16 was carried out. The obtained results are described in Table 10.

Comparative example 23, 24

Nitric acid in Comparative Example 16 was replaced by phosphoric acid 5.50% by mass (Comparative Example 23) or acetic acid 4.66% by mass (Comparative Example 24), n-butylamine was added at 0.89% by mass, and copper powder 4000ppm and titanium powder 360ppm were added to the resulting liquid to carry out The same test as in Comparative Example 16 was carried out. The obtained results are described in Table 11.

Comparative Example 25

The same test as in Example 14 was performed except that the concentration of acidic ammonium fluoride in Example 14 was 0.55% by mass. The obtained results are described in Table 11.

Comparative Examples 26-35

The glass substrates for corrosion evaluation were dipped and etched in the same etchant as in Comparative Examples 16 to 25, and the corrosion rates were calculated and evaluated for the obtained samples, respectively. The results obtained are summarized in Tables 12 and 13.

Comparative example 36-45

The substrates for corrosion evaluation of silicon dioxide were dipped and etched in the same etchant as in Comparative Examples 16 to 25, and the corrosion rates were calculated and evaluated for the obtained samples. The obtained results are summarized in Tables 14 and 15.

Comparative example 46-55

The substrates for corrosion evaluation of silicon nitride were dipped and etched in the same etchant as in Comparative Examples 16 to 25, and the respective corrosion rates were calculated and evaluated for the obtained samples. The results obtained are summarized in Tables 16 and 17.

[Table 6]

※1 Mitsubishi Gas Chemical Co., Ltd. product

※2 Manufactured by Wako Pure Chemical Industries, Ltd.

※3 Acid ammonium fluoride, manufactured by STELLA CHEMIFA CORPORATION

※4 5-Amino-1H-tetrazole, manufactured by Wako Pure Chemical Industries, Ltd.

※5 amine compounds:

Example 11: 3-methoxypropylamine (manufactured by Wako Pure Chemical Industries, Ltd.)

Example 12: Methylbutylamine (manufactured by ALDRICH Corporation)

Example 13: 2-Amino-1-butan-1-ol (manufactured by Wako Pure Chemical Industries, Ltd.)

Example 14: n-butylamine (manufactured by Wako Pure Chemical Industries, Ltd.)

Example 15: Cyclohexylamine (manufactured by Wako Pure Chemical Industries, Ltd.)

※6 Phenylurea, manufactured by Wako Pure Chemical Industries, Ltd.

※7 Manufactured by Wako Pure Chemical Industries, Ltd.

※8 Manufactured by Wako Pure Chemical Industries, Ltd.

[Table 7]

[Table 8]

[Table 9]

[Table 10]

※1 Mitsubishi Gas Chemical Co., Ltd. product

※2 acid ingredients:

Comparative Examples 16, 17, 19, and 20: nitric acid, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Example 18: Sulfuric acid, manufactured by Wako Pure Chemical Industries, Ltd.

※3 Acid ammonium fluoride, manufactured by STELLA CHEMIFA CORPORATION

*4 5-Amino-1H-tetrazole, manufactured by Wako Pure Chemical Industries, Ltd.

※5 base compounds:

Comparative Example 16: Potassium hydroxide, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Example 17: Ammonia, manufactured by Mitsubishi Gas Chemical Co., Ltd.

Comparative Example 18: n-butylamine, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Example 19: Diethylenetriamine, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Example 20: 2-(2-Aminoethoxy)ethanol, manufactured by Wako Pure Chemical Industries, Ltd.

※6 Phenylurea, manufactured by Wako Pure Chemical Industries, Ltd.

※7 Manufactured by Wako Pure Chemical Industries, Ltd.

※8 Manufactured by Wako Pure Chemical Industries, Ltd.

[Table 11]

※1 Mitsubishi Gas Chemical Co., Ltd. product

※2 acid ingredients:

Comparative Examples 21, 22, and 25: nitric acid, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Example 23: Phosphoric acid, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Example 24: Acetic acid, manufactured by Wako Pure Chemical Industries, Ltd.

※3 Acid ammonium fluoride, manufactured by STELLA CHEMIFA CORPORATION

*4 5-Amino-1H-tetrazole, manufactured by Wako Pure Chemical Industries, Ltd.

※5 base compounds:

Comparative Example 21: Dimethylamine, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Example 22: Piperazine, manufactured by Wako Pure Chemical Industries, Ltd.

Comparative Examples 23, 24, and 25: n-butylamine, manufactured by Wako Pure Chemical Industries, Ltd.

※6 Phenylurea, manufactured by Wako Pure Chemical Industries, Ltd.

※7 Manufactured by Wako Pure Chemical Industries, Ltd.

※8 Manufactured by Wako Pure Chemical Industries, Ltd.

[Table 12]

[Table 13]

[Table 14]

[Table 15]

[Table 16]

[Table 17]

In Examples 11 to 30 (Tables 6 to 9) using the etching solution of the present invention, etching was possible within a desired time, and the wiring shape after etching was favorable. In addition, it is judged that both the corrosion rate and hydrogen peroxide decomposition rate of glass, silicon dioxide, or silicon nitride are sufficiently suppressed, and it can be used even if the metal concentration is increased.

On the other hand, in Comparative Examples 16, 17, 26, 27, 36, 37, 46, and 47 (Table 10, Tables 12 to 17) using potassium hydroxide and ammonia, which are commonly used alkali components, glass and silica Both the corrosion rate and the decomposition rate of hydrogen peroxide were high, making it unusable. In Comparative Example 18 (Table 10) using sulfuric acid as the acid, the etching rate became too fast, and the wiring on the substrate disappeared after etching for a predetermined time.

In Comparative Examples 19, 20, 21, and 22 in which an amine compound other than the present invention was used as the base component, the stability of hydrogen peroxide was remarkably lowered, so that it could not be used. Furthermore, in Comparative Example 19, etching residue (smearing) of the titanium layer occurred, and the wiring shape could not be measured (Tables 10 and 11).

In Comparative Examples 23, 33, 43, and 53 (Tables 11 to 17) using phosphoric acid as the acid component, the titanium powder was not dissolved in the etching solution, and evaluation as an etching solution was not possible.

In Comparative Examples 24, 34, 44, and 54 (Tables 11 to 14) using acetic acid as an acidic component described in Patent Document 2, the pH could not be adjusted to a predetermined range, and titanium powder could not be dissolved in the etching solution.

In Comparative Examples 35, 45, and 55 (Tables 12 to 17) in which the concentration of the fluorine compound exceeded the desired concentration, the etching rate of glass, silicon dioxide, or silicon nitride was significantly increased, making it unusable.

Industrial availability

The etchant of the present invention can be suitably used for etching a multilayer thin film including a copper layer mainly composed of copper and a titanium layer mainly composed of titanium, especially a multilayer thin film in which a copper layer is laminated on a titanium layer. The etching method using this etchant can collectively etch a wiring having a multilayer thin film including a copper layer and a titanium layer, and can obtain a good shape of the wiring after etching, so that high productivity can be achieved. In addition, the consumption of hydrogen peroxide is small, which is excellent economically.

Claims (12)

1. An etchant, which is an etchant for etching a multilayer film laminated on a substrate, and the substrate uses more than one selected from glass, silicon dioxide and silicon nitride, and the multilayer film comprising a copper layer mainly composed of copper and a titanium layer mainly composed of titanium, The etching solution is an aqueous solution comprising the following components and has a pH value of 1.5 to 2.5: (A) the concentration of hydrogen peroxide is 4.5～7.5% by mass; (B) the concentration of nitric acid is 0.8～6 mass %; (C) The concentration of the fluorine compound is 0.2 to 0.5% by mass; (D) The concentration of azoles is 0.14 to 0.3% by mass; (E) The concentration of the amine compound is 0.4 to 10% by mass, and the amine compound is selected from linear or branched alkyl groups having 2 to 5 carbon atoms optionally substituted with one or more methoxy groups. Alkylamine (E1), having 1 or 2 linear or branched hydroxyalkyl groups with 2 to 5 carbons, and optionally having 1 or 2 linear or branched hydroxyalkyl groups with 2 carbons One of alkanolamine (E2) having an alkyl group of ∼5, diamine (E3) having a linear or branched alkylene group having 2 to 5 carbon atoms, and cyclohexylamine (E4) above; and (F) The concentration of the hydrogen peroxide stabilizer is 0.005 to 0.1% by mass. 2. The etching solution according to claim 1, wherein (C) the fluorine compound is at least one selected from hydrofluoric acid, ammonium fluoride, and acidic ammonium fluoride. 3. The etching solution according to claim 1, wherein (D) the azole is 5-amino-1H-tetrazole. 4. The etching solution according to claim 1, wherein, (E) amine compound is selected from isopropanolamine, 3-amino-1-propanol, N-butylethanolamine, N,N-dimethylamino -2-propanol, 2-methoxyethylamine, cyclohexylamine, n-butylamine, dibutylamine, tert-butylamine, N-methyl-n-butylamine, 1,4-diaminobutane, 2-amino- One or more of 1-butanol, 5-amino-1-pentanol, 3-methoxypropylamine, 2-dimethylaminoethanol and 2-aminoethanol. 5. The etching solution according to claim 1, wherein (F) the hydrogen peroxide stabilizer is at least one selected from the group consisting of phenylurea and phenolsulfonic acid. 6. The etchant according to claim 1, wherein the top CD loss is 2.5 μm or less, the bottom CD loss is 1.5 μm or less and the tailing is 0.4 μm or less. 7. The etchant according to claim 1, wherein the etching rate of glass is 60 nm/minute or less. 8. etching solution according to claim 1, wherein, the etching speed of silicon dioxide and silicon nitride is /min or less. 9. The etchant according to claim 1, wherein an appropriate etching time for a multilayer thin film including a copper layer mainly composed of copper and a titanium layer mainly composed of titanium is 80 seconds to 140 seconds. 10. etching solution according to claim 1, wherein, in this etching solution, add copper 4000ppm and titanium 360ppm, and the stability of the hydrogen peroxide in this etching solution when preserving 2 hours at 50 ℃ is 0.075%/ hours or less. 11. The etchant according to claim 1, wherein the multilayer thin film laminated on a substrate selected from one or more of glass, silicon dioxide, and silicon nitride is a titanium layer with titanium as the main component. A copper layer with copper as the main component is laminated on top. 12. A method for etching a multilayer film comprising a copper layer having copper as a main component and a titanium layer having titanium as a main component, characterized in that the multilayer film laminated on a substrate is in accordance with claims 1 to 11 In contact with the etching solution described in any one, the substrate uses one or more selected from glass, silicon dioxide, and silicon nitride, and the multilayer film includes a copper layer with copper as the main component and titanium as the main component. Composition of titanium layer.