Etching solution composition not containing volatile acid

Abstract

The present invention relates to an etchant composition that does not contain acetic acid and can be used to form metal wiring on an array substrate. The present invention provides an etchant composition that contains 40 to 65 weight percent phosphoric acid, 2 to 10 weight percent nitric acid, 1 to 10 weight percent non-volatile organic acid, an ammonium salt compound, and an amino acid, wherein the sum of the ammonium salt compound content and the amino acid content is 2 to 10 weight percent. The etchant composition of the present invention can control residue in a single silver (Ag) film or multiple films containing silver (Ag), increase the usable life of the etchant, and reduce the volatility of the etchant, thereby forming uniform wiring on a large-area array substrate.

Description

Technical Field

[0001] The present invention relates to an etching solution composition containing no volatile acid, and in particular to an etching solution composition containing no volatile acid that can be used when forming metal wiring of an array substrate. Background Art

[0002] Thin film transistors (TFTs) are used as circuits for applying specific signals to individual pixels for driving in liquid crystal display devices, organic light emitting diode (OLED) display devices, and the like.

[0003] In the past, aluminum (Al) reflectors were used as the metal for the reflective film, but now multiple layers of materials such as indium tin oxide or indium zinc oxide containing silver (Ag) are used. However, multiple layers containing silver (Ag) have poor adhesion to the underlying substrate and exhibit high etching rates, which can easily lead to uneven wiring.

[0004] Therefore, there is a need for an etching solution composition that can improve the stability and cost of silver (Ag) etching solutions by improving film warping, uneven pattern formation and residue formation in the array due to over-etching, and short service life due to the short life of the existing etching solution. Summary of the Invention

[0005] Problems to be solved by the present invention

[0006] Therefore, an object of the present invention is to provide an etching solution composition that can achieve residue control on a single silver (Ag) film or multiple films containing silver (Ag), and can form uniform wiring on a large-area array substrate and increase the service life of the etching solution.

[0007] Another object of the present invention is to provide an etching solution composition that can extend the use time and improve stability by using an etching solution that does not contain volatile acid.

[0008] Solutions to Problems

[0009] To achieve the above objectives, the etching solution composition of the present invention comprises: 40 to 65 weight percent phosphoric acid, 2 to 10 weight percent nitric acid, 1 to 10 weight percent non-volatile organic acid, an ammonium salt compound, an amino acid, and the remainder water. The sum of the ammonium salt compound and the amino acid content is 2 to 10 weight percent.

[0010] The etching solution composition may not contain volatile acid.

[0011] 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.

[0012] The content of the ammonium salt compound may be 1 to 9 wt %.

[0013] The ammonium salt compound may be selected from the group consisting of ammonium oxalate, ammonium phosphate, ammonium acetate, and mixtures thereof.

[0014] The amino acid may be present in an amount of 1 to 9% by weight.

[0015] 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.

[0016] The etching solution composition can be used to etch a single silver (Ag) film or multiple films containing silver (Ag).

[0017] Effects of the Invention

[0018] The etching solution composition of the present invention, which does not contain volatile acids, can control the residue of a single silver (Ag) film or multiple films containing silver (Ag) when etching the multiple films and increase the use time of the etching solution. It can also reduce the volatility of the etching solution, thereby forming uniform wiring on a large-area array substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a scanning electron microscope photograph of a sample including a triple film of indium oxide film-silver-indium oxide film and a photoresist pattern when phosphoric acid changes in an example of the present invention.

[0020] Figure 2 This is a scanning electron microscope photograph of a sample including a triple film of indium oxide film-silver-indium oxide film and a photoresist pattern when nitric acid changes in an example of the present invention.

[0021] Figure 3 This is a scanning electron microscope photograph of a sample including a triple film of indium oxide film-silver-indium oxide film and a photoresist pattern when a non-volatile organic acid changes in an example of the present invention.

[0022] Figure 4 This is a scanning electron microscope photograph of a sample including a triple film of indium oxide film-silver-indium oxide film and a photoresist pattern when the ammonium salt and the amino acid are changed in an example of the present invention.

[0023] Figure 51 is a scanning electron microscope photograph of a sample including a triple film of an indium oxide film-silver-indium oxide film and a photoresist pattern when the types of non-volatile organic acids are different in an embodiment of the present invention.

[0024] Figure 6 This is a scanning electron microscope photograph of a sample including a triple film of indium oxide film-silver-indium oxide film and a photoresist pattern as a comparative example.

[0025] Figure 7 This is a scanning electron microscope photograph of a sample including a triple film of indium oxide film-silver-indium oxide film and a photoresist pattern as a comparative example. DETAILED DESCRIPTION

[0026] Next, the present invention will be described in more detail.

[0027] 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. The etching solution composition is used for etching a silver (Ag) metal film or a multiple film (metal film) containing silver (Ag).

[0028] In the etching solution composition of the present invention, phosphoric acid serves as a main etchant and dissolves Ag ions that encounter nitric acid ions in order to etch a multi-layer film containing silver (Ag).

[0029] 3AgNO3+H3PO4→Ag3PO4+3HNO3

[0030] The phosphoric acid content may be 40 to 65 weight percent, specifically 42 to 64 weight percent, relative to 100 weight percent of the entire etching solution composition. If the phosphoric acid content is less than 40 weight percent, some portions may not be etched. If the phosphoric acid content exceeds 65 weight percent, the amount of indium tin oxide (ITO) used in the multilayer film etched may be reduced while the amount of silver (Ag) etched may be increased, leading to pattern loss.

[0031] The nitric acid serves as an oxidant and can oxidize the surfaces of indium tin oxide (ITO) and silver (Ag).

[0032] 3Ag+4HNO3→3AgNO3+2H2O+NO

[0033] The nitric acid content may be 2 to 10% by weight, specifically 3 to 10% by weight, relative to 100% by weight of the entire etching solution composition. If the nitric acid content is less than 2% by weight, uneven etching rates may make it difficult to accurately form a pattern. Thin film residue may also cause short circuits, leading to product defects when the pattern is completed. If the nitric acid content exceeds 10% by weight, it may be difficult to adjust the etching rate of indium oxide, increasing the risk of pattern loss.

[0034] The non-volatile organic acid can be used as auxiliary oxidant to regulate the etching speed of indium tin oxide 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, etc. With respect to 100% by weight of overall silver (Ag) etching solution composition, the content of the non-volatile organic acid can be 1 to 10% by weight, specifically 2 to 8% by weight. When the content of the non-volatile organic acid is less than 1% by weight, the problem of forming the tip of oxide film in multiple films may occur because the etching speed of indium tin oxide (ITO) decreases. When exceeding 10% by weight, although the etching speed of oxide film can be promoted, the problem of uneven exposure of silver deposited film and further uneven pattern formation may occur due to the excessive etching of oxide film, and the problem of being unable to dissolve when manufacturing etching solution may occur.

[0035] The ammonium salt compound and amino acid act as corrosion inhibitors to regulate 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 weaker corrosion inhibitors than ammonium salts. By using the ammonium salt compound and amino acid together, the etching rate can be adjusted.

[0036] The ammonium ions in the ammonium salt compound, as a salt-state additive, may include at least one selected from the group consisting of ammonium oxalate, ammonium phosphate, and ammonium acetate, but are not limited thereto. Other ammonium salts are unstable when manufactured into etching solutions, thus causing heat generation and decreased stability.

[0037] 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. Adding other amino acids may result in excessive bubbles and brown fumes due to decomposition by strong acids, making them unsuitable for the production of etching solutions.

[0038] The ammonium salt compound and the amino acid may each be present in an amount of 1 to 9 weight percent, specifically 2 to 8 weight percent, relative to 100 weight percent of the total etching solution composition. If the ammonium salt compound and the amino acid content are each less than 1 weight percent, it may be difficult to control the silver etching rate and the etching may be uneven, leading to pattern loss. If the ammonium salt compound and the amino acid content are each greater than 9 weight percent, while the silver corrosion resistance may be improved, the etching rate of the oxide film may be reduced, resulting in residual silver and oxide film residues and the formation of residues.

[0039] The total content of the ammonium salt compound and the amino acid may be 2 to 10% by weight relative to 100% by weight of the entire etching solution composition. If the total content of the ammonium salt compound and the amino acid exceeds 10% by weight, it may be difficult to control the etching rate, resulting in irregular etching or excessive etching, or residual silver and oxide residues forming residues.

[0040] Furthermore, if the ammonium salt compound and the amino acid are not used together as an etching solution composition but only one of them is used at a content of 1 wt % to 9 wt %, problems such as irregular etching, over-etching, or residue formation may occur.

[0041] The etching solution composition of the present invention can be used as an etching solution for forming metal wiring used in thin film transistor liquid crystal display devices, etc. The metal wiring is used as a reflective film and for transmitting electrical signals, and can be used to etch silver (Ag) metal films.

[0042] The silver (Ag) metal film may include a single silver (Ag) film or multiple films including silver (Ag). The multiple films including silver (Ag) may, for example, include 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 alloy films thereof. The multiple films may include a double film, a triple film, or multiple films having more than one layer. Specifically, the silver (Ag) metal film includes an indium tin oxide film (ITO), an indium zinc oxide alloy film, an indium oxide film, or a mixture thereof on a silver (Ag) film, and may, for example, include a multiple film consisting of ITO / Ag / ITO.

[0043] At present because comprising highly volatile acetic acid or propionic acid etc. in etching solution composition, therefore composition can be changed greatly along with the service life of etching solution, thereby causes the problem that the service life of etching solution shortens.In order to solve problem as above, the present invention can be by getting rid of volatile acid (acetic acid) as etching solution composition and promoting the service life of etching solution compared with the current etching solution comprising acetic acid, thereby when manufacturing thin film transistor (Thin Firm Transistor, TFT) liquid crystal display device or organic light emitting diode (OLED, Organic Light Emitting Diode) display device, save the cost of use of etching solution, and because do not comprise highly volatile acetic acid or propionic acid etc. when manufacturing etching solution, therefore can complete manufacturing with cheap price.Described volatile acid can be example with acetic acid, propionic acid, formic acid etc., and wherein acetic acid is the fastest acid of volatilization, and when acetic acid content reduces, the content of other acids will increase, and therefore the ability that metal is etched also will increase.

[0044] Therefore, the etching solution composition of the present invention can improve the uniformity of wiring formed after etching an array substrate and extend the usable time of the etching solution when manufacturing the array substrate, thereby easily achieving process control and saving manufacturing equipment and manufacturing costs. If necessary, a general additive can also be used. In addition, the residue of a single silver (Ag) film or multiple films containing silver (Ag) can also be controlled.

[0045] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0046] [Examples 1 to 35] Manufacturing of etching solution

[0047] An etching solution was prepared by mixing phosphoric acid, nitric acid, an ammonium salt compound, an amino acid, and a non-volatile organic acid according to the composition ratios listed in Table 1 below. The ammonium salt compound (ammonium acetate) was used at 5% by mass, the amino acid (glycine) was used at 5% by mass, and the non-volatile organic acid (citric acid) was used at 5% by mass. The composition ratios listed in Table 1 below are expressed in weight percent.

[0048] In Table 1 below, Examples 1 to 13 are etching solution compositions containing different phosphoric acid contents, Examples 14 to 17 are etching solution compositions containing different nitric acid contents, Examples 18 to 22 are etching solution compositions containing different volatile organic acid contents, Examples 23 to 32 are etching solution compositions containing different ammonium salt and amino acid contents, and Examples 33 to 35 are etching solution compositions containing different types of non-volatile organic acids. In Examples 33 to 35, lactic acid, glycolic acid, and ascorbic acid were used as the non-volatile organic acids, respectively.

[0049] [Table 1]

[0050]

[0051] [Comparative Examples 1 to 15] Manufacturing of etching solution

[0052] An etching solution was prepared by mixing phosphoric acid, nitric acid, acetic acid, an ammonium salt compound, an amino acid, and a non-volatile organic acid according to the composition ratios listed in Table 2 below. The nitric acid, acetic acid, ammonium salt compound, amino acid, and non-volatile organic acid were the same as those used in Examples 1 to 35. However, the ammonium salt compound content was 11% by weight in Comparative Example 8, the amino acid content was 11% by weight in Comparative Example 9, the non-volatile organic acid content was 11% by weight in Comparative Example 6, the combined content of the ammonium salt compound and amino acid content was 12% by weight in Comparative Examples 12 and 13, and 5% by weight of acetic acid and propionic acid were each used in Comparative Examples 14 and 15. The composition ratios listed in Table 2 below are expressed in weight %.

[0053] [Table 2]

[0054]

[0055] [Test Examples 1 to 3] Analysis of etching solution composition over 24 hours

[0056] The etching solutions prepared in Example 8, Comparative Example 10, and Comparative Example 11 were analyzed for their temporal changes from 0 to 24 hours. The 24-hour temporal changes in the etching solution composition were analyzed by ion chromatography after sampling the etching solutions at 0 and 24 hours. The resulting values ​​are shown in Tables 3 to 5 below.

[0057] [Table 3]

[0058]

[0059] [Table 4]

[0060]

[0061] [Table 5]

[0062]

[0063] Tables 3 to 5 above compare the results of compositions containing volatile acids (acetic acid or propionic acid) (Test Examples 2 and 3) and a composition without volatile acids (Test Example 1) to confirm their 24-hour temporal characteristics. The results of Test Examples 2 and 3, compared to the results of Test Example 1, demonstrate a dramatic change in the etching solution's composition over time. Compositional changes such as a phosphoric acid content exceeding 65% by weight and a decrease in the acetic and propionic acid contents by 7% or more can lead to overetching when used as an etching solution, resulting in an inability to uniformly etch array wiring.

[0064] [Test Example 4] Etching solution characteristics analysis

[0065] The ITO / Ag / ITO triple film was etched using the etching solution composition manufactured in Examples 1 to 35 and Comparative Examples 1 to 15. In particular, after 200% over-etching based on the endpoint detection (EPD) of the upper ITO / Ag layer, the endpoint detection (EPD) and critical dimension deviation (CD-Bias) as well as the residue characteristics of Ag and ITO were analyzed, and the results are shown in Table 6 below. As a parameter, the endpoint detection (EPD) maintenance, critical dimension deviation (CD-Bias) maintenance and Ag and ITO residue were confirmed using a lateral cross-sectional photograph of an electron scanning microscope by comparing the results of the continuous test for 0 hours and 24 hours over time. The test method for each condition is as follows. Regarding endpoint detection (EPD), the time when Ag is etched is judged and recorded visually when evaluating with the etching solution, and the difference between 0 hours and 24 hours is confirmed. The time change is limited to a range of less than 5 seconds.

[0066] Critical dimension deviation (CD-Bias) and Ag and ITO residues were measured using a scanning electron microscope (SEM) and confirmed through images. The resulting images are shown in the figure.

[0067] Scanning electron microscope photographs of samples including a triple film and a photoresist pattern etched using the etching solution compositions prepared in Examples 1 to 35 and Comparative Examples 1 to 15 are shown below. Figures 1 to 7 shown.

[0068] In Table 6 below, endpoint detection (EPD) values ​​with a change of less than 5 seconds within 24 hours are marked as O, while values ​​with a change of 5 seconds or more are marked as X. Furthermore, critical dimension deviation (CD-Bias) values ​​with a change of less than 0.2 μm within 24 hours are marked as O, while values ​​with a change of 0.2 μm or more are marked as X. CD-Bias refers to the distance between the end of the photoresist pattern and the end of the silver pattern, and the appropriate range is 0.5 μm or less.

[0069] The residues of Ag and ITO were analyzed by scanning electron microscope (SEM) images.

[0070] [Table 6]

[0071]

[0072]

[0073] As shown in Table 6, in Examples 1 to 24 and Examples 26 to 31, when the proportions of phosphoric acid, nitric acid, ammonium compounds, amino acids, and organic acid additives are appropriate, a uniform etching level can be achieved.

[0074] In contrast, in Comparative Examples 1 to 9 and Comparative Examples 12 to 13, when the content of each component exceeded the range or was excluded, poor pattern formation occurred due to non-etching, over-etching, or formation of Ag or ITO residues.

[0075] Furthermore, Comparative Examples 10, 11, 14, and 15, which examined the time-dependent properties of etchant compositions using acetic acid and propionic acid, showed that decreasing the acetic acid content resulted in a decrease in the usable life of the etchant and an increase in the critical dimension deviation (CD-Bias). This is because the etchant compositions do not contain acetic acid (a volatile acid), minimizing the effects of reduced acetic acid content.

Claims

1. An etching solution composition, characterized in that Include: Phosphoric acid 40 to 65% by weight; nitric acid 2 to 10% by weight; 1 to 10 wt% non-volatile organic acid; ammonium salt compounds; as well as, amino acids; The sum of the content of the ammonium salt compound and the content of the amino acid is 2 to 10% by weight, The content of the amino acid is 1 to 9% by weight. The amino acid is selected from the group consisting of alanine, glycine, asparagine, aspartic acid, pyroglutamic acid, hippuric acid, glutamic acid, and mixtures thereof.

2. The etching solution composition according to claim 1, wherein: 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, wherein: The content of the ammonium salt compound is 1 to 9% by weight.

4. The etching solution composition according to claim 1, wherein: 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, wherein: The etching solution composition is used for etching a single silver (Ag) film or multiple films containing silver (Ag).

6. The etching solution composition according to claim 5, wherein: The multi-film including silver (Ag) includes 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 alloy films thereof.

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