A highly selective Ag-Al composite etching solution composition

Abstract

This invention provides a highly selective Ag-Al composite etching solution composition, relating to the field of metal film etching technology. The highly selective Ag-Al composite etching solution composition comprises phosphoric acid, sulfuric acid, potassium hydrogen sulfate, ammonium sulfate, 1-hydroxybenzotriazole, 3-amino-1,2,4-triazole, dimethyl dithiophosphate, and an organic alcohol. This invention overcomes the shortcomings of existing technologies, effectively etching Al while causing almost no erosion of Ag, effectively preventing the problem of over-etching Ag in traditional processes.

Description

Technical Field

[0001] This invention relates to the field of metal film etching technology, and more specifically to a highly selective Ag-Al composite etching solution composition. Background Technology

[0002] In the field of display technology, OLED panels, with their outstanding characteristics such as self-emission, high contrast, wide viewing angle, and thinness, have become the core direction of current and future display technology development. The performance of OLED panels is closely related to the precision of the manufacturing process, among which the precise etching of metal electrodes is one of the key processes to ensure panel display quality and production efficiency.

[0003] The limitations of traditional etching solutions mainly include: In the traditional OLED panel manufacturing process, the etching process for multilayer electrode structures containing metals such as silver (Ag) and aluminum (Al) follows a specific procedure. Typically, phosphoric acid-based etching solutions play a crucial role in this process, primarily designed for effective etching of Al to achieve precise shaping of the electrode structure. However, in practice, a thorny problem arises: due to the chemical similarities between Ag and Al, phosphoric acid-based etching solutions inevitably etch Ag along with Al.

[0004] Meanwhile, traditional etching processes for Ag also employ a non-phosphate-based Ag etching solution for pretreatment. This step aims to initially remove some Ag material and optimize the metal film structure. However, even with this two-step etching method, it remains difficult to precisely control the etching degree of the Ag metal film. The "collateral damage" to Ag by phosphate-based etching solutions and the difficulty in controlling the Ag etching depth during the overall etching process easily lead to over-etching of Ag.

[0005] Excessive etching of Ag can lead to a series of serious consequences. From an electrode structure perspective, it disrupts the integrity and uniformity of the electrodes, significantly reducing their conductivity. From an electrical performance standpoint, it can cause short circuits, leakage, and other electrical faults, severely impacting the display performance of OLED panels, resulting in issues such as uneven display and color deviation. It also reduces the long-term reliability of the panel. Ultimately, these adverse effects manifest as a significant drop in product yield, increasing production costs and reducing the company's competitiveness in the market.

[0006] Therefore, developing a novel etching solution capable of precisely distinguishing and selectively etching different metal materials has become a pressing technical challenge for the industry. In particular, for composite metal layers containing Ag and Al, developing an etching solution that effectively etches Al while minimizing the etching effect on Ag is crucial for improving the precision of OLED panel manufacturing processes and increasing product yield. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a highly selective Ag-Al composite etching solution composition that can effectively etch Al while having almost no corrosive effect on Ag, effectively preventing the problem of excessive Ag etching in traditional processes.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A highly selective Ag-Al composite etching solution composition, wherein the composite etching solution composition comprises the following substances in the indicated mass percentages: phosphoric acid (H3PO4) 50.00%-55.00%, sulfuric acid (H2SO4) 5.50%-6.50%, potassium hydrogen sulfate (PBS) 0.50%-0.90%, ammonium sulfate (AS) 0.20%-0.60%, 1-hydroxybenzotriazole (HOBT) 0.25%-0.30%, 3-amino-1,2,4-triazole (AT) 0.41%-0.45%, dimethyl dithiophosphate (DMDTP) 0.02%-0.05%, organic alcohol 1.5%-2.5%, and water is added to make up to 100%; and the ratio of 3-amino-1,2,4-triazole to 1-hydroxybenzotriazole is controlled to be ≥1.5.

[0010] Preferably, the organic alcohol is at least one of polyether diol (PPG), butanediol (BDO), and triethylene glycol (TEG).

[0011] Preferably, the composite etching solution composition is capable of selectively etching the Al layer.

[0012] Preferably, the composite etching solution composition is used by spray etching, and the spray pressure is 0.1-0.2 MPa.

[0013] Preferably, the composite etching solution composition is used at a temperature of 35-45°C.

[0014] This invention provides a highly selective Ag-Al composite etching solution composition, which has the following advantages compared with the prior art:

[0015] The etching solution of this invention, by setting a phosphoric acid system and simultaneously compounding 1-hydroxybenzotriazole, 3-amino-1,2,4-triazole, dimethyl dithiophosphate, and other substances, achieves highly efficient and selective etching of Al, and improves the etching efficiency of Al, while having almost no corrosive effect on Ag. This effectively solves the problem of excessive Ag etching in traditional processes. Furthermore, the overall etching solution has high etching efficiency and good effect on Al, improves production efficiency, and significantly improves the manufacturing yield of OLED panels, providing strong technical support for the further development of OLED display technology. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the measurement locations of the upper Al-Ti S / E value and the lower Al-Ti S / E value after etching Ti / Al / Ti by the etching solution in an embodiment of the present invention;

[0017] Figure 2 This is an electron microscope image of a Ti / Al / Ti substrate treated with etching solution S1 for 160 seconds in an embodiment of the present invention.

[0018] Figure 3 This is an electron microscope image of a Ti / Al / Ti substrate treated with etching solution S2 for 160 s in an embodiment of the present invention.

[0019] Figure 4 This is an electron microscope image of a Ti / Al / Ti substrate treated with etching solution S3 for 160 seconds in an embodiment of the present invention.

[0020] Figure 5 This is an electron microscope image of a Ti / Al / Ti substrate treated with etching solution S4 for 160 seconds in an embodiment of the present invention.

[0021] Figure 6 This is an electron microscope image of a Ti / Al / Ti substrate treated with etching solution S5 for 160 seconds in an embodiment of the present invention.

[0022] Figure 7 This is an electron microscope image of a Ti / Al / Ti substrate treated with etching solution S6 for 160 seconds in an embodiment of the present invention.

[0023] Figure 8 This is an electron microscope image of an ITO / Ag / ITO substrate treated with etching solution S1 for 160 seconds in an embodiment of the present invention.

[0024] Figure 9 This is an electron microscope image of an ITO / Ag / ITO substrate treated with etching solution S2 for 160 seconds in an embodiment of the present invention.

[0025] Figure 10 This is an electron microscope image of an ITO / Ag / ITO substrate treated with etching solution S3 for 160 seconds in an embodiment of the present invention.

[0026] Figure 11 This is an electron microscope image of an ITO / Ag / ITO substrate treated with etching solution S4 for 160 seconds in an embodiment of the present invention.

[0027] Figure 12 This is an electron microscope image of an ITO / Ag / ITO substrate treated with etching solution S5 for 160 seconds in an embodiment of the present invention.

[0028] Figure 13This is an electron microscope image of an ITO / Ag / ITO substrate treated with etching solution S6 for 160 seconds in an embodiment of the present invention.

[0029] Figure 14 This is an electron microscope image of an ITO / Ag / ITO substrate after 160s of treatment with etching solution S1 to remove the top layer of ITO in an embodiment of the present invention.

[0030] Figure 15 This is an electron microscope image of an ITO / Ag / ITO substrate after 160s of treatment with etching solution S2 to remove the top layer of ITO in an embodiment of the present invention.

[0031] Figure 16 This is an electron microscope image of an ITO / Ag / ITO substrate after 160s of treatment with etching solution S3 to remove the top layer of ITO in an embodiment of the present invention.

[0032] Figure 17 This is an electron microscope image of an ITO / Ag / ITO substrate after 160s of treatment with etching solution S4 to remove the top layer of ITO in an embodiment of the present invention.

[0033] Figure 18 This is an electron microscope image of an ITO / Ag / ITO substrate after 160s of etching with etching solution S5 to remove the top layer of ITO in an embodiment of the present invention.

[0034] Figure 19 This is an electron microscope image of an ITO / Ag / ITO substrate after 160s of treatment with etching solution S6 to remove the top layer of ITO in an embodiment of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example:

[0037] Prepare different etching solutions according to the formulas in Table 1 below (the organic alcohol used in the table is butanediol), with the remainder being water:

[0038] Table 1 Formulations of different etching solutions

[0039]

[0040] The performance of each of the above-prepared etching solutions was tested:

[0041] Ti / Al / Ti and ITO (indium tin oxide) / Ag / ITO substrates were used as test materials to verify the etching effects of each etching solution on Al, ITO, and Ag:

[0042] Etching verification conditions:

[0043] The substrate was etched by spraying, with the spraying pressure controlled at 0.1 MPa, the etching temperature at 40°C, and the etching time at 160 s.

[0044] 1. Etching experiments on Al:

[0045] The Ti / Al / Ti substrates were etched using the etching verification conditions described above with different etching solutions. After etching, the upper Al-Ti S / E value and lower Al-Ti S / E value of each etched substrate were recorded, where S / E represents the lateral etching amount. The specific measurement locations of the upper Al-Ti S / E value and lower Al-Ti S / E value are as follows: Figure 1 As shown in Table 2, the specific test results are as follows, and the electron microscope image of the substrate after etching is shown in the figure. Figures 2-7 As shown.

[0046] Table 2 Results of etching Ti / Al / Ti substrates with different etching solutions

[0047]

[0048] As shown in the table above, the addition of HOBT and DMDTP can effectively improve the etching efficiency of the etching solution on Al. Furthermore, when the ratio of 3-amino-1,2,4-triazole to 1-hydroxybenzotriazole is less than 1.5 (experimental group 3), the etching efficiency of the etching solution on Al also decreases.

[0049] 2. Etching experiments for ITO:

[0050] Each group of etching solutions was used to etch the ITO / Ag / ITO substrate for 160 seconds under the above etching verification conditions. The presence of corrosion marks on the ITO layer after etching was observed. Specific results are shown below. Figure 8-13 and Table 3 below:

[0051] Table 3. Etching results of ITO layer in ITO / Ag / ITO substrate by different etching solutions

[0052]

[0053] The above tests show that etching solutions S1-S6 have no corrosive effect on the ITO layer.

[0054] 3. Etching experiment for Ag

[0055] The top layer of ITO on the ITO / Ag / ITO substrate was removed using KBX-618A ITO etchant. Then, each etchant was used under the aforementioned etching verification conditions to perform a spray etching process on the ITO / Ag / ITO substrate with the top layer removed for 160 seconds. The presence of corrosion on the Ag layer was observed. Specific results are shown in Table 4 below. Figures 14-19 .

[0056] Table 4. Etching results of different etching solutions on the Ag layer in ITO / Ag / ITO substrates

[0057]

[0058] The above tests show that etching solutions S1-S6 have no corrosive effect on the Ag layer. Therefore, the experiments confirm that etching solutions S1-S6 have high selectivity for Al, and that etching solutions S1 and S2 are highly efficient at etching Al.

[0059] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly selective Ag-Al composite etching solution composition, characterized in that, The composite etching solution composition comprises the following substances in the indicated mass percentages: 50.00%-55.00% phosphoric acid, 5.50%-6.50% sulfuric acid, 0.50%-0.90% potassium hydrogen sulfate, 0.20%-0.60% ammonium sulfate, 0.25%-0.30% 1-hydroxybenzotriazole, 0.41%-0.45% 3-amino-1,2,4-triazole, 0.02%-0.05% dimethyl dithiophosphate, and 1.5%-2.5% organic alcohol, with water added to make up to 100%; and the ratio of 3-amino-1,2,4-triazole to 1-hydroxybenzotriazole is controlled to be ≥1.5; the organic alcohol is at least one selected from polyether diol, butanediol, and triethylene glycol; the composite etching solution composition can selectively etch the Al layer without corroding silver.

2. The composite etching solution composition according to claim 1, characterized in that: The composite etching solution composition is used for spray etching, and the spray pressure is 0.1-0.2 MPa.

3. The composite etching solution composition according to claim 1, characterized in that: The composite etching solution composition is used at a temperature of 35-45°C.

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