CN113881938A

CN113881938A - Etching solution composition containing no volatile acid

Info

Publication number: CN113881938A
Application number: CN202110745093.0A
Authority: CN
Inventors: 金荣光; 姜东浒; 金圣雄; 车敬雄; 裴正贤; 申贤哲
Original assignee: Dongjin Semichem Co Ltd
Current assignee: Dongjin Semichem Co Ltd
Priority date: 2020-07-03
Filing date: 2021-07-01
Publication date: 2022-01-04
Also published as: TW202202660A; KR20220004560A

Abstract

The present invention relates to an etching solution composition that does not contain acetic acid and can be used for forming metal wiring of an array substrate. The present invention can provide an etching solution composition comprising 40 to 65 wt% of phosphoric acid, 2 to 10 wt% of nitric acid, 1 to 10 wt% of a nonvolatile organic acid, an ammonium salt compound, and an amino acid, wherein a content of the ammonium salt compound and a content of the amino acid are 2 to 10 wt%. The etching solution composition of the invention can control residues of a silver (Ag) single film or a multiple film containing the silver (Ag) when etching the multiple film, increase the service time of the etching solution, and reduce the volatility of the etching solution, thereby forming uniform wiring on a large-area array substrate.

Description

Etching solution composition containing no volatile acid

Technical Field

The present invention relates to an etching solution composition containing no volatile acid, and more particularly, to an etching solution composition containing no volatile acid, which can be used for forming a metal wiring of an array substrate.

Background

Thin Film Transistors (TFTs) are used as circuits for applying specific signals to respective pixels and driving them in liquid crystal display devices, Organic Light Emitting Diode (OLED) display devices, and the like.

Among them, as a metal used for a reflective film, an aluminum (Al) reflective plate has been used in the past, but a multilayer film (Layer) such as indium tin oxide or indium zinc oxide containing silver (Ag) has been used at present. However, since the adhesion of the multiple Layer (Layer) including silver (Ag) to the lower substrate is reduced and the etching rate is excessively high, the uneven wiring is easily formed.

Therefore, there is a need for an etchant composition that can improve the problems of lift-off of a thin film in the existing etchant, formation of uneven patterns in an array and formation of residues due to over-etching, and the problem of excessively short service time of a silver (Ag) etchant due to a short lifetime of the existing etchant, thereby improving the stability thereof and saving costs.

Disclosure of Invention

Problems to be solved by the invention

Accordingly, an object of the present invention is to provide an etchant composition that can control residues of a single silver (Ag) film or a multiple silver (Ag) film, and can form uniform wiring on a large-area array substrate and increase the service life of the etchant.

Another object of the present invention is to provide an etching solution composition which can improve the working time and stability by using an etching solution containing no volatile acid.

Means for solving the problems

In order to achieve the above object, an etchant composition of the present invention comprises: 40 to 65% by weight of phosphoric acid, 2 to 10% by weight of nitric acid, 1 to 10% by weight of a nonvolatile organic acid, an ammonium salt compound, an amino acid, and a residual content of water. The sum of the content of the ammonium salt compound and the content of the amino acid is 2 to 10% by weight.

The etching solution composition may not contain a volatile acid.

The non-volatile organic acid may be selected from the group consisting of succinic acid, malonic acid, malic acid, maleic acid, citric acid, tartaric acid, and mixtures thereof.

The content of the ammonium salt compound may be 1 to 9% by weight.

The ammonium salt compound may be selected from the group consisting of ammonium oxalate, ammonium phosphate, ammonium acetate, and mixtures thereof.

The amino acid content may be 1 to 9 wt%.

The amino acid may be selected from the group consisting of alanine, glycine, asparagine, aspartic acid, pyroglutamic acid, hippuric acid, glutamic acid and mixtures thereof.

The etching solution composition may be used to etch a single film of silver (Ag) or a multi-film including silver (Ag).

Effects of the invention

The etching solution composition not containing volatile acid of the present invention can control residues of a silver (Ag) single film or a silver (Ag) multiple film when etching the multiple film, increase the use time of the etching solution, and reduce the volatility of the etching solution, thereby forming uniform wiring on a large-area array substrate.

Drawings

Fig. 1 is a scanning electron microscope photograph of a sample including an indium oxide film-silver-indium oxide film triple film and a photoresist pattern when phosphoric acid is changed in an embodiment of the present invention.

Fig. 2 is a scanning electron microscope photograph of a sample including an indium oxide film-silver-indium oxide film triple film and a photoresist pattern when nitric acid is changed in an embodiment of the present invention.

Fig. 3 is a scanning electron microscope photograph of a sample including an indium oxide film-silver-indium oxide film triple film and a photoresist pattern when a nonvolatile organic acid is changed in an embodiment of the present invention.

Fig. 4 is a scanning electron microscope photograph of a sample including an indium oxide film-silver-indium oxide film triple film and a photoresist pattern when ammonium salts and amino acids are changed in the example of the present invention.

Fig. 5 is a scanning electron microscope photograph of a sample including an indium oxide film-silver-indium oxide film triple film and a photoresist pattern, when the type of the non-volatile organic acid is different in the embodiment of the present invention.

Fig. 6 is a scanning electron microscope photograph of a sample of a triple film including an indium oxide film-silver-indium oxide film and a photoresist pattern of a comparative example.

Fig. 7 is a scanning electron microscope photograph of a sample of a triple film including an indium oxide film-silver-indium oxide film and a photoresist pattern of a comparative example.

Detailed Description

Next, the present invention will be described in more detail.

The present invention relates to an etching solution composition containing no volatile acid, comprising phosphoric acid, nitric acid, a non-volatile organic acid, an ammonium salt compound, and an amino acid, for etching a silver (Ag) metal film or a multiple film (metal film) containing silver (Ag).

In the etching solution composition of the present invention, phosphoric acid is used as a main etchant to dissolve silver (Ag) ions that have come into contact with nitric acid ions in order to etch a multiple film containing Ag.

3AgNO₃+H₃PO₄→Ag₃PO₄+3HNO₃

The phosphoric acid may be contained in an amount of 40 to 65 wt%, specifically 42 to 64 wt%, with respect to 100 wt% of the entire etching solution composition. In the case where the content of the phosphoric acid is less than 40 wt%, a problem that a portion is not etched may be caused, and in the case where it exceeds 65 wt%, a problem that a pattern is lost may be caused because an etching amount of Indium Tin Oxide (ITO) used in a multi-layer film is decreased and an etching amount of silver (Ag) is increased.

The nitric acid is used as an oxidant to oxidize Indium Tin Oxide (ITO) and silver (Ag) surfaces.

3Ag+4HNO₃→3AgNO₃+2H₂O+NO

The nitric acid may be contained in an amount of 2 to 10 wt%, specifically 3 to 10 wt%, with respect to 100 wt% of the entire etching solution composition. When the content of the nitric acid is less than 2 wt%, it may cause a problem that it is difficult to accurately form a pattern due to non-uniform etching rate, may cause a short-circuit problem due to a thin film remaining, and may further cause a product failure when the pattern is completed, and when it exceeds 10 wt%, it may cause a problem that it is difficult to adjust the etching rate of indium oxide, thereby increasing a pattern loss.

The non-volatile organic acid is used as an auxiliary oxidant, and the etching speed of the indium tin oxide can be adjusted by reducing the decomposition speed of the nitric acid. The non-volatile organic acid can be exemplified by succinic acid, malonic acid, malic acid, maleic acid, citric acid, tartaric acid, and the like. The non-volatile organic acid may be contained in an amount of 1 to 10 wt%, and specifically, 2 to 8 wt%, with respect to 100 wt% of the entire silver (Ag) etchant composition. When the content of the non-volatile organic acid is less than 1 wt%, there may be a problem in that the tip of the oxide film is formed in the multi-layer film due to a decrease in the etching rate of Indium Tin Oxide (ITO), and when it exceeds 10 wt%, although the etching rate of the oxide film may be increased, there may be a problem in that the silver deposition film is not uniformly exposed due to over-etching of the oxide film and the formed pattern is not uniform, and there may be a problem in that it cannot be dissolved when the etching solution is manufactured.

The ammonium salt compound and the amino acid act as an anticorrosive agent, and can adjust the etching rate of silver (Ag) and Indium Tin Oxide (ITO). Ammonium salt compounds are strong corrosion inhibitors, while amino acids including amino acid salts can be used as weak corrosion inhibitors compared to ammonium salts. By using the ammonium salt compound and the amino acid together, the etching rate can be adjusted.

The ammonium ion in the ammonium salt compound may include at least one selected from the group consisting of ammonium oxalate, ammonium phosphate, ammonium acetate (ammonium acetate), and the like as an additive in a salt state, but is not limited thereto. Other ammonium-containing salts are unstable when made into etching solutions and thus cause heat generation and a decrease in stability.

The amino acid may be in the form of a salt, and may include at least one selected from the group consisting of alanine, glycine, asparagine, aspartic acid, pyroglutamic acid, hippuric acid, and glutamic acid, but is not limited thereto. When other amino acids are added, excessive bubbles and brown fumes are generated due to decomposition by strong acid, and therefore, the addition of other amino acids is not suitable for the production of etching solutions.

The contents of the ammonium salt compound and the amino acid may be 1 to 9 wt%, and specifically 2 to 8 wt%, respectively, with respect to 100 wt% of the entire etching solution composition. When the content of the ammonium salt compound and the amino acid is less than 1 wt%, the etching rate of silver may be difficult to control and the etching may be uneven, thereby causing pattern loss, and when the content exceeds 9 wt%, the corrosion resistance of silver may be improved, but the etching rate of the oxide film may be decreased, thereby causing a problem that silver and residues of the oxide film remain and form residues.

The sum of the content of the ammonium salt compound and the content of the amino acid may be 2 to 10% by weight with respect to 100% by weight of the entire etching solution composition. In the case where the sum of the content of the ammonium salt compound and the content of the amino acid exceeds 10% by weight, there may be a problem that irregular etching or over-etching or residues of silver and oxides remain and a residue is formed because it is difficult to control the etching rate.

Further, when the ammonium salt compound and the amino acid are not used as the etching solution composition at the same time and only one of them is used in an amount of 1 to 9 wt%, there is a possibility that irregular etching, over-etching or residue formation may occur.

The etching solution composition of the present invention can be used as an etching solution for forming metal wiring used in a thin film transistor liquid crystal display device or the like. The metal wiring is used as a reflective film and for transmitting an electrical signal, and particularly may be used for etching a silver (Ag) metal film.

The silver (Ag) metal film may include a single film of silver (Ag) or a multi-film including silver (Ag). The silver (Ag) -containing multilayer film may include, for example, a silver (Ag) film and an oxide film selected from the group consisting of an indium oxide film, an indium tin oxide film (ITO), an indium zinc oxide film (IZO), an indium gallium oxide film (IGO), and an alloy film thereof. The multiple film may comprise a double film, a triple film, or more layers of multiple films. The silver (Ag) metal film specifically includes an indium tin oxide film (ITO), an indium zinc oxide alloy film, an indium oxide film, and a mixture thereof on the silver (Ag) film, and may include a multiple film composed of ITO/Ag/ITO, for example.

At present, because the etching solution composition contains highly volatile acetic acid or propionic acid, etc., the composition is greatly changed along with the service time of the etching solution, thereby causing the problem of shortening the service time of the etching solution. In order to solve the above problems, the present invention can improve the usable time of the etching solution compared to the conventional etching solution containing acetic acid by removing volatile acid (acetic acid) as the etching solution composition, thereby saving the cost of the etching solution when manufacturing a Thin Film Transistor (TFT) liquid crystal display device or an Organic Light Emitting Diode (OLED) display device, and can be manufactured at a low cost because the etching solution does not contain highly volatile acetic acid or propionic acid, etc. The volatile acid may be exemplified by acetic acid, propionic acid, formic acid, etc., wherein acetic acid is the most rapidly volatile acid, and the content of other acids increases as the content of acetic acid decreases, and thus the ability to etch metals also increases.

Therefore, the etchant composition of the present invention can improve uniformity in forming a wiring after etching an Array (Array) substrate and extend the usable time of the etchant in manufacturing the Array (Array) substrate, thereby easily realizing process control and saving a manufacturing apparatus and manufacturing costs. General-purpose additives may also be used as necessary. Furthermore, it is also possible to control residues of a single film of silver (Ag) or a multiple film including silver (Ag).

The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

Examples 1 to 35]Production of etching solution

An etching solution was produced by mixing phosphoric acid, nitric acid, an ammonium salt compound, an amino acid, and a nonvolatile organic acid according to the composition ratio shown in table 1 below. The ammonium salt compound (ammonium acetate) was used at 5 mass%, the amino acid (glycine) was used at 5 mass%, and the nonvolatile organic acid (citric acid) was used at 5 mass%. The unit of the composition ratio described in table 1 below is wt%.

In table 1 below, examples 1 to 13 are etching solution compositions having different phosphoric acid contents, examples 14 to 17 are etching solution compositions having different nitric acid contents, examples 18 to 22 are etching solution compositions having different volatile organic acid contents, examples 23 to 32 are etching solution compositions having different ammonium salts and amino acid contents, and examples 33 to 35 are etching solution compositions having different types of nonvolatile organic acids. In examples 33 to 35, lactic acid, glycolic acid, and ascorbic acid were used as nonvolatile organic acids, respectively.

[ Table 1]

[ comparative examples 1 to 15]Production of etching solution

An etching solution was produced by mixing phosphoric acid, nitric acid, acetic acid, an ammonium salt compound, an amino acid, and a nonvolatile organic acid according to the composition ratio shown in table 2 below. The nitric acid, acetic acid, ammonium salt compound, amino acid and nonvolatile organic acid were the same as those used in examples 1 to 35. However, the content of the ammonium salt compound was 11% by weight in comparative example 8, the content of the amino acid was 11% by weight in comparative example 9, the content of the nonvolatile organic acid was 11% by weight in comparative example 6, the sum of the content of the ammonium salt compound and the content of the amino acid was 12% by weight in comparative examples 12 and 13, and 5% by weight of each of acetic acid and propionic acid was used in comparative examples 14 and 15. The unit of the composition ratio described in table 2 below is wt%.

[ Table 2]

[ test examples 1 to 3]Analysis of etching solution composition with time at 24 hours

The etching solutions prepared in example 8, comparative example 10, and comparative example 11 were analyzed for changes over time from 0 hour to 24 hours. The analysis of the etching solution composition with respect to the change over time of 24 hours was performed by Ion Chromatography (Ion Chromatography) after collecting the etching solutions for 0 hour and 24 hours, and the results thereof are shown in tables 3 to 5 below.

[ Table 3]

[ Table 4]

[ Table 5]

Tables 3 to 5 show the results of comparing the compositions (test examples 2 and 3) to which the volatile acid (acetic acid or propionic acid) was added with the compositions (test example 1) to which no volatile acid was added, in order to confirm the characteristics over time of 24 hours. Referring to the table, it was confirmed that the results of test examples 2 and 3 exhibited the change characteristics of the etching solution due to the rapid change of the composition with the passage of time, as compared with the results of test example 1. When a composition change occurs in which the content of phosphoric acid exceeds 65% by weight and the content of acetic acid and propionic acid is reduced by 7% by weight or more, a problem of over-etching may be caused in the case of using as an etching solution composition and thus the Array (Array) wiring may not be uniformly etched.

[ test example 4]Analysis of etching liquid Properties

The ITO/Ag/ITO triple film was etched using the etching solution compositions manufactured in examples 1 to 35 and comparative examples 1 to 15. In particular, after 200% over-etching was performed based on End Point Detection (EPD) of the upper ITO/Ag layer, End Point Detection (EPD), critical dimension variation (CD-Bias), and Ag and ITO residue characteristics were analyzed, and the results are shown in table 6 below. As parameters, End Point Detection (EPD) maintenance, critical dimension deviation (CD-Bias) maintenance, and Ag and ITO residues were confirmed by comparing the results of 0 hour and 24 hour continuous tests with time evaluation using a lateral cross-sectional photograph of an electron scanning microscope. The test methods for each condition are as follows. For End Point Detection (EPD), the time at which Ag was etched was visually judged and recorded and the difference between 0 hour and 24 hours was confirmed at the time of evaluation using the etching solution. The time variation is limited to a range within 5 seconds.

The critical dimension deviation (CD-Bias) and the Ag and ITO residues were measured by a Scanning Electron Microscope (SEM) and confirmed by images. The resulting image is shown.

Scanning electron micrographs of samples containing the triple film and the photoresist pattern etched using the etchant compositions manufactured in examples 1 to 35 and comparative examples 1 to 15 described above are shown in fig. 1 to 7 described below.

In Table 6 below, O is marked when the End Point Detection (EPD) is maintained for less than 5 seconds with a change within 24 hours, X is marked when the change reaches 5 seconds or more, and O is marked when the critical dimension deviation (CD-Bias) is maintained for less than 0.2 μm with a change within 24 hours, and X is marked when the change reaches 0.2 μm or more. The critical dimension deviation (CD-Bias) is a distance between the end of the photoresist pattern and the end of the silver, and is preferably in a range of 0.5 μm or less.

Ag. The ITO residues were analyzed by Scanning Electron Microscope (SEM) from the images.

[ Table 6]

As shown in table 6, in examples 1 to 24 and examples 26 to 31, uniform etching levels were exhibited when the proportions of phosphoric acid, nitric acid, ammonium compound, amino acid, and organic acid additive were appropriate.

In contrast, in comparative examples 1 to 9 and 12 to 13, when the content of each composition is out of the range or excluded, a problem of pattern formation may be caused by not being etched, over-etched, or forming residues of Ag, ITO.

In addition, comparative examples 10, 11, 14, and 15 were the results of confirming the temporal characteristics when acetic acid and propionic acid were used as the etching solution composition, and exhibited a decrease in the usable time of the etching solution and an increase in the critical dimension deviation (CD-Bias) when the acetic acid content was decreased. This is because acetic acid (volatile acid) is not contained as the etching liquid composition, and thus the phenomenon caused by the reduction of acetic acid can be minimized.

Claims

1. An etchant composition, comprising:

40 to 65 weight percent phosphoric acid;

2 to 10 weight percent nitric acid;

1 to 10 wt% of a non-volatile organic acid;

an ammonium salt compound; and the number of the first and second groups,

an amino acid;

the sum of the content of the ammonium salt compound and the content of the amino acid is 2 to 10% by weight.

2. The etching solution composition according to claim 1, characterized in that:

the non-volatile organic acid is selected from the group consisting of succinic acid, malonic acid, malic acid, maleic acid, citric acid, tartaric acid, and mixtures thereof.

3. The etching solution composition according to claim 1, characterized in that:

the content of the ammonium salt compound is 1 to 9% by weight.

4. The etching solution composition according to claim 1, characterized in that:

the ammonium salt compound is selected from the group consisting of ammonium oxalate, ammonium phosphate, ammonium acetate, and mixtures thereof.

5. The etching solution composition according to claim 1, characterized in that:

the amino acid content is 1 to 9% by weight.

6. The etching solution composition according to claim 1, characterized in that:

the amino acid is selected from the group consisting of alanine, glycine, asparagine, aspartic acid, pyroglutamic acid, hippuric acid, glutamic acid and mixtures thereof.

7. The etching solution composition according to claim 1, characterized in that:

the etching solution composition is used for etching a single film of silver (Ag) or a multiple film including silver (Ag).

8. The etching solution composition according to claim 7, characterized in that:

the multiple film comprising silver (Ag) comprises a silver (Ag) film; and an oxide film selected from the group consisting of an indium oxide film, an indium tin oxide film, an indium zinc oxide film, an indium gallium oxide film, and an alloy film thereof.