Metallic alkaline etching solution for panel industry and preparation method thereof

Abstract

This invention provides an alkaline etching solution for etching copper in the panel industry, comprising copper chloride, ammonium chloride, ammonia, a protective agent, a wetting agent, and water. Preferably, the protective agent is 8-mercaptoquinoline, and the wetting agent is 2-phenoxyethanol.

Description

Technical Field

[0001] This invention relates to the field of electronic chemicals technology in the liquid crystal display thin film transistor (TFT) industry, specifically to an alkaline etching solution for etching copper used in the panel industry and its preparation method. Background of the Invention

[0002] In recent years, to meet the needs of end users, LCD displays have gradually developed towards larger sizes and higher resolutions. However, larger panels increase the impedance of the conductors and reduce signal transmission speed. To adapt to the development of the panel industry, replacing aluminum and its alloys with copper and its alloys, which have lower conductivity and excellent anti-electromigration properties, can effectively reduce conductor impedance and current loss, improve signal transmission speed, and simplify the manufacturing process of driver ICs.

[0003] Etching is a crucial process in TFT-LCD manufacturing, primarily involving the removal of material through specific physical or chemical reactions. Etching is categorized into wet etching and dry etching, with wet etching enjoying long-term industry application due to its high productivity and selectivity. Currently, the most widely used wet etching solutions in industry are acidic copper chloride etching solutions and alkaline copper chloride etching solutions. Alkaline copper chloride etching solutions utilize the divalent copper ammonia complex Cu(NH3)4Cl2, formed by the complexation reaction of copper chloride with ammonia, as the copper etchant, reacting with oxygen and NH4+. + and Cl - The reaction process regenerates the copper etching agent. However, wet etching also has some drawbacks. For example, alkaline copper chloride etchant has an isotropic etching effect, which can lead to lateral etching. Excessive lateral etching can reduce the linewidth of conductors and affect the electrical properties of the product. Therefore, developing a copper etchant that can reduce lateral etching is particularly important. Summary of the Invention

[0004] The present invention solves the above problems by providing an improved alkaline copper chloride etching solution.

[0005] Specifically, the present invention provides an alkaline etching solution for etching copper for use in the panel industry, which comprises copper chloride, ammonium chloride, ammonia, a protective agent, a wetting agent and water.

[0006] In a specific implementation, the present invention provides an alkaline etching solution for etching copper in the panel industry, comprising 110-150 g / L copper chloride, 140-160 g / L ammonium chloride, 20-30% ammonia, 6-10 mg / L revetment agent, 0.4-1.0 g / L wetting agent, and the remainder being water.

[0007] In a preferred embodiment, the concentration of the bank protection agent is 8 mg / L.

[0008] In a preferred embodiment, the concentration of the wetting agent is 0.6 g / L.

[0009] In a specific implementation scheme, the bank protection agent is selected from methyltetrazole, mercaptopropylene glycol, benzimidazole, benzotriazole, 2-mercaptobenzothiazole, 8-hydroxyquinoline or 8-mercaptoquinoline.

[0010] In a preferred embodiment, the bank protection agent is 8-mercaptoquinoline.

[0011] As used in this article, 8-mercaptoquinoline has the following structure:

[0012]

[0013] In a specific implementation, the wetting agent is selected from 2-phenoxyethanol.

[0014] As used herein, 2-phenoxyethanol has the following structure:

[0015]

[0016] In a specific implementation, the pH value of the alkaline etching solution of the present invention is 8.0-9.0, for example 8.5.

[0017] Therefore, in a preferred embodiment, the present invention provides an alkaline etching solution for etching copper for use in the panel industry, comprising 110-150 g / L copper chloride, 140-160 g / L ammonium chloride, 20-30% ammonia, 8 mg / L 8-mercaptoquinoline, 0.6 g / L 2-phenoxyethanol, with the remainder being water.

[0018] The present invention also provides a method for preparing an alkaline etching solution as described herein, comprising:

[0019] 1) Weigh out the predetermined amounts of ammonium chloride, bank protection agent, and wetting agent, add them to the water, and stir until completely dissolved.

[0020] 2) Weigh out the predetermined amount of copper chloride and add it to the solution from step 1), stirring until completely dissolved.

[0021] 3) Add an appropriate amount of ammonia to the solution in step 2) to adjust the pH of the solution to the predetermined value.

[0022] In a specific implementation scheme, the predetermined amounts of each component in the method are as follows: 110-150 g / L copper chloride, 140-160 g / L ammonium chloride, 20-30% ammonia water, 6-10 mg / L bank protection agent, and 0.4-1.0 g / L wetting agent.

[0023] In a preferred embodiment, the concentration of the bank protection agent is 8 mg / L.

[0024] In a preferred embodiment, the concentration of the wetting agent is 0.6 g / L.

[0025] In a preferred embodiment, the bank protection agent is 8-mercaptoquinoline.

[0026] As used in this article, 8-mercaptoquinoline has the following structure:

[0027]

[0028] In a specific implementation, the wetting agent is selected from 2-phenoxyethanol.

[0029] As used herein, 2-phenoxyethanol has the following structure:

[0030]

[0031] In a preferred embodiment, the pH value in the method is 8.0-9.0, for example 8.5.

[0032] Beneficial effects of the present invention

[0033] The inventors added 8-mercaptoquinone as a resilient agent and 2-phenoxyethanol as a wetting agent to a traditional alkaline copper chloride etching solution, resulting in a significant reduction in lateral etching during the etching process and a substantial increase in the etching factor from 2.8 to 4.0. Adding only 8-mercaptoquinone or 2-phenoxyethanol did not produce this significant improvement in lateral etching. This indicates that 8-mercaptoquinone and 2-phenoxyethanol can work synergistically to improve the lateral etching effect of the etching solution. Furthermore, the inventors also found that structurally similar compounds to 8-mercaptoquinone could not achieve this effect, proving that the synergistic effect of 8-mercaptoquinone and 2-phenoxyethanol in the alkaline etching solution of this invention is specific. Example

[0034] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0035] Example 1:

[0036] Preparation of alkaline etching solution for etching copper-containing metal layers:

[0037] 1) Weigh out 150 g / L ammonium chloride, 6 mg / L 8-mercaptoquinoline, and 0.4 g / L 2-phenoxyethanol, add them to water, and stir until completely dissolved.

[0038] 2) Weigh 135 g / L copper chloride and add it to the solution from step 1), stirring until completely dissolved.

[0039] 3) Add approximately 22% ammonia to the solution from step 2) to adjust the pH of the solution to 8.5.

[0040] The etching process using the etching solution of this embodiment includes the following steps:

[0041] 1) Pour the etching solution into the etching tank, set the temperature of the etching tank to 55℃, and set the pressure of the etching solution nozzle of the etching machine to 2 kg / cm². 2 The etching operation begins; the automatic detection and feeding control mechanism automatically feeds and replenishes the various components in the etching solution to maintain the specific gravity at the specified value.

[0042] 2) Take an etching factor test circuit board with a size of 620×540mm, a copper thickness of 1oz, a development line width and line spacing of 50.8μm, and a pure copper etching rate test board with a size of 500×300mm×1.5mm and place them in an etching machine for spray corrosion test. Use the methods known in this industry to calculate the etching rate and etching factor K. The results are shown in Table 1.

[0043] Example 2:

[0044] Preparation of alkaline etching solution for etching copper-containing metal layers:

[0045] 1) Weigh out 150 g / L ammonium chloride, 8 mg / L 8-mercaptoquinoline, and 0.6 g / L 2-phenoxyethanol, add them to water, and stir until completely dissolved.

[0046] 2) Weigh 135 g / L copper chloride and add it to the solution from step 1), stirring until completely dissolved.

[0047] 3) Add approximately 23% ammonia to the solution from step 2) to adjust the pH of the solution to 8.5.

[0048] As described in Example 1, the etching process of this example is performed using the etching solution, and the etching rate and etching factor K are calculated. The results are shown in Table 1.

[0049] Example 3:

[0050] Preparation of alkaline etching solution for etching copper-containing metal layers:

[0051] 1) Weigh out 150 g / L ammonium chloride, 10 mg / L 8-mercaptoquinoline, and 1.0 g / L 2-phenoxyethanol, add them to water, and stir until completely dissolved.

[0052] 2) Weigh 135 g / L copper chloride and add it to the solution from step 1), stirring until completely dissolved.

[0053] 3) Add approximately 25% ammonia to the solution from step 2) to adjust the pH of the solution to 8.5.

[0054] As described in Example 1, the etching process of this example is performed using the etching solution, and the etching rate and etching factor K are calculated. The results are shown in Table 1.

[0055] Comparative Example 1:

[0056] Preparation of alkaline etching solution for etching copper-containing metal layers:

[0057] 1) Weigh 150g / L of ammonium chloride and add it to water, stirring until completely dissolved.

[0058] 2) Weigh 135 g / L copper chloride and add it to the solution from step 1), stirring until completely dissolved.

[0059] 3) Add about 20% ammonia to the solution in step 2) to adjust the pH of the solution to 8.5.

[0060] As described in Example 1, the etching process of this example is performed using the etching solution, and the etching rate and etching factor K are calculated. The results are shown in Table 1.

[0061] Comparative Example 2:

[0062] Preparation of alkaline etching solution for etching copper-containing metal layers:

[0063] 1) Weigh out 150 g / L ammonium chloride and 8 mg / L 8-mercaptoquinoline, add them to water, and stir until completely dissolved.

[0064] 2) Weigh 135 g / L copper chloride and add it to the solution from step 1), stirring until completely dissolved.

[0065] 3) Add approximately 23% ammonia to the solution from step 2) to adjust the pH of the solution to 8.5.

[0066] As described in Example 1, the etching process of this example is performed using the etching solution, and the etching rate and etching factor K are calculated. The results are shown in Table 1.

[0067] Comparative Example 3:

[0068] Preparation of alkaline etching solution for etching copper-containing metal layers:

[0069] 1) Weigh out 150 g / L ammonium chloride and 0.6 g / L 2-phenoxyethanol, add them to water, and stir until completely dissolved.

[0070] 2) Weigh 135 g / L copper chloride and add it to the solution from step 1), stirring until completely dissolved.

[0071] 3) Add approximately 23% ammonia to the solution from step 2) to adjust the pH of the solution to 8.5.

[0072] As described in Example 1, the etching process of this example is performed using the etching solution, and the etching rate and etching factor K are calculated. The results are shown in Table 1.

[0073] Comparative Example 4:

[0074] Preparation of alkaline etching solution for etching copper-containing metal layers:

[0075] 1) Weigh out 150 g / L ammonium chloride, 8 mg / L 8-hydroxyquinoline, and 0.6 g / L 2-phenoxyethanol, add them to water, and stir until completely dissolved.

[0076] 2) Weigh 135 g / L copper chloride and add it to the solution from step 1), stirring until completely dissolved.

[0077] 3) Add approximately 23% ammonia to the solution from step 2) to adjust the pH of the solution to 8.5.

[0078] As described in Example 1, the etching process of this example is performed using the etching solution, and the etching rate and etching factor K are calculated. The results are shown in Table 1.

[0079] Etching solution Etching rate (μm / min) Etching factor Example 1 30.2 3.9 Example 2 29.8 4.0 Example 3 28.9 3.8 Comparative Example 1 30.5 2.8 Comparative Example 2 29.6 3.0 Comparative Example 3 30.4 2.8 Comparative Example 4 28.5 3.1

[0080] The results above show that the combined use of 8-mercaptoquinoline and 2-phenoxyethanol synergistically improves the lateral etching of alkaline copper chloride etching solution, and its effect on the etching rate is negligible. However, the combined use of 8-hydroxyquinoline and 2-phenoxyethanol does not exhibit this synergistic effect.

[0081] In the description of this specification, the references to terms such as "an embodiment," "specific embodiment," and "example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. An alkaline etching solution for etching copper used in the panel industry, characterized in that: It contains copper chloride, ammonium chloride, ammonia, bank protection agent, wetting agent, and water; The alkaline etching solution contains 110-150 g / L copper chloride, 140-160 g / L ammonium chloride, 20-30% ammonia, 6-10 mg / L bank protection agent, and 0.4-1.0 g / L wetting agent; The bank protection agent is 8-mercaptoquinoline; The wetting agent is selected from 2-phenoxyethanol; The pH value of the alkaline etching solution is 8.0-9.0; Adding 8-mercaptoquinoline as a bank protection agent and 2-phenoxyethanol as a wetting agent to the alkaline copper chloride etching solution significantly reduced the lateral etching during etching operations, and increased the etching factor from 2.8 to 4.

0. 8-mercaptoquinoline and 2-phenoxyethanol can work synergistically to improve the lateral etching effect of the etching solution.

2. A method for preparing the alkaline etching solution of claim 1, comprising: 1) Weigh out the predetermined amounts of ammonium chloride, bank protection agent, and wetting agent, add them to the water, and stir until completely dissolved. 2) Weigh out the predetermined amount of copper chloride and add it to the solution from step 1), stirring until completely dissolved. 3) Add an appropriate amount of ammonia to the solution in step 2) to adjust the pH of the solution to the predetermined value.

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