A MoTi film composite etchant composition

Abstract

This invention provides a MoTi film composite etchant composition, relating to the field of metal film etching technology. The composite etchant composition comprises hydrogen peroxide, ammonium hydrogen fluoride, a weak organic acid, a corrosion inhibitor, cis-1,4-cyclohexanedicarboxylic acid, 3-amino-1,2,4-triazole, a complexing agent, iminodiacetic acid, an organic alcohol, and water; and the ratio of ammonium hydrogen fluoride to cis-1,4-cyclohexanedicarboxylic acid is ≥0.2. This invention overcomes the shortcomings of existing technologies, effectively improving the etching efficiency of MoTi films while reducing erosion of adjacent metal layers, achieving precise control of the etching rate, ensuring etching stability, and significantly improving product yield.

Description

Technical Field

[0001] This invention relates to the field of metal film etching technology, and more specifically to a MoTi film composite etchant composition. Background Technology

[0002] With the development of the display industry, the size of LCD panels is constantly increasing, and the precision requirements for TFT manufacturing are becoming increasingly stringent. Therefore, copper, a metal material with lower resistance, is being used more widely. During copper wiring, direct contact with other films such as silicon is inevitable. Due to the inherent properties of copper, it is prone to oxidation and diffusion into other films, leading to device performance failure. Therefore, high-performance metal or alloy films are often used as transition layers between copper and other films. The most commonly used transition layer metals are molybdenum and molybdenum alloys (such as Mo, Nb, and MTD). Later, through continuous research, titanium was discovered to have excellent stability, barrier properties, thermodynamic effects, and electrical properties, gradually replacing other alloy materials and becoming a popular material for transition layers. The innovative application of film materials has also spurred the continuous updating and iteration of etching solutions to adapt to the development of panel manufacturing.

[0003] While conventional etching solutions are effective for etching copper and molybdenum alloys, they are less effective for etching copper and molybdenum-titanium alloys due to the unique properties of titanium. This can lead to under-etching or over-etching, resulting in residues or broken lines. Furthermore, the etching uniformity deteriorates over time, severely impacting the yield of subsequent products. Therefore, a superior molybdenum-titanium etching solution is urgently needed to overcome the limitations of traditional etching agents and achieve uniformity and stability during the etching process. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a MoTi film composite etchant composition that can effectively improve the etching efficiency of MoTi films while reducing erosion of adjacent metal layers, achieving precise control of the etching rate, ensuring etching stability, and significantly improving product yield.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A MoTi film composite etchant composition, the composition comprising the following raw materials in the indicated mass percentages: hydrogen peroxide (H2O2) 10.0%-12.0%, ammonium bifluoride (ABF) 0.05%-0.1%, weak organic acid 4.0%-5.0%, corrosion inhibitor 0.5%-1.5%, cis-1,4-cyclohexanedicarboxylic acid (C-CHDC) 0.2%-0.5%, 3-amino-1,2,4-triazole (AT) 0.3%-0.5%, complexing agent 0.4%-0.6%, iminodiacetic acid (IDA) 1.5%-2.5%, organic alcohol 2.0%-3.0%, and water to make up to 100%; wherein the ratio of ammonium bifluoride to cis-1,4-cyclohexanedicarboxylic acid is ≥0.2.

[0007] Preferably, the weak organic acid is any one or a combination of citric acid (CA), salicylic acid (SA), tartaric acid (TA), lactic acid (LAC), and acetic acid (HAc).

[0008] Preferably, the corrosion inhibitor is triethanolamine (TEA).

[0009] Preferably, the complexing agent is obtained by mixing tetrasodium iminodisuccinate (IDS) and monosodium glutamate (MSG) in a mass ratio of 6-8:1.

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

[0011] Preferably, the etchant composition is used by spraying at a pressure of 0.1-0.2 MPa and an etching temperature of 25-35°C, with the etching time controlled to be extended by 50%-70% during etching.

[0012] Preferably, the etchant composition is used to etch copper and molybdenum-titanium films.

[0013] This invention provides a MoTi film composite etchant composition, which has the following advantages compared with the prior art:

[0014] This invention incorporates a low hydrogen peroxide content in the etchant to enhance its safety. In many formulations, as the copper ion content increases towards the end of the etching process, H2O2 decomposition accelerates, leading to sudden boiling. Reducing the hydrogen peroxide concentration largely avoids this problem. Furthermore, based on the etching characteristics of MoTi, a weak organic acid is used as the primary etchant, combined with the complexing agent iminodiacetic acid for etching, resulting in a more stable system environment. By controlling the proportions of cis-1,4-cyclohexanedicarboxylic acid and fluorinated compounds, the etching rate can be controlled, ensuring the smoothness and precision of the etched morphology. Comprehensive adjustments to the composition and dosage of the complexing agent, corrosion inhibitor, and pH buffer further enhance the overall etching stability, guaranteeing a high yield of the final etched product. Attached Figure Description

[0015] Figure 1 The image shows an electron microscope image of experimental group 1 after etching treatment in this embodiment of the invention (1 in the image is CD bias; 2 is Tail; 3 is Tip; 4 is T / A).

[0016] Figure 2 The image shows an electron microscope image of experimental group 3 after etching treatment in this embodiment of the invention (1 in the image is CD bias; 2 is Tail; 3 is Tip; 4 is T / A). Detailed Implementation

[0017] 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.

[0018] Example:

[0019] Different etchants were prepared according to the formulas in Table 1 below (the etching inhibitor used in the table is triethanolamine (TEA), the weak organic acid is citric acid (CA), the complexing agent is tetrasodium iminodisuccinate (IDS) and monosodium glutamate (MSG) mixed in a mass ratio of 7:1; the organic alcohol is triethylene glycol (TEG), and the balance is water).

[0020] Table 1

[0021]

[0022] Alternatively, referring to the formulation in Table S1 above, the complexing agent was replaced with pure tetrasodium iminodisuccinate to prepare etchant S6.

[0023] The performance of each of the above-prepared etchants was tested:

[0024] 1. Select substrates from the same batch with MTD (molybdenum-titanium-nickel alloy) / Cu / MoTi (molybdenum-titanium alloy) specifications of 100 / 3000 / 200Å for etching tests:

[0025] The etching method is as follows: Spray etching is performed at 30℃, with the spray pressure controlled at 0.1 MPa and the etching time controlled at approximately 70% over-etching. The etchants S1-S6 prepared above are used for treatment, as shown in Table 2 below:

[0026] Table 2

[0027]

[0028] Etching effect confirmation: The CD bias (difference between the original size of the metal line and the original size of the photoresist after etching), Taper Angle (T / A) (the angle formed by the top and bottom of the metal layer), Tail (the length of the edge protrusion / irregular part remaining after etching of the molybdenum-titanium alloy layer (MoTi)), and Tip (the distance from the end of the topmost MTD to the metal) of the substrate were confirmed by SEM under each etching treatment. The specific results are shown in Table 3 below:

[0029] Table 3

[0030]

[0031] As shown in the table above, adding C-CHDC and IDA to the etchant can effectively reduce the etching time. Furthermore, the addition of a certain proportion of C-CHDC and ABF can reduce the T / A value and CD bias value, improving etching accuracy and ensuring precise matching between the photoresist and the etched structure. Although reducing the addition of IDA effectively lowered the T / A value in Experimental Group 5, the CD bias value and Tail value were significantly higher than in Experimental Group 1, and the overall etching time was also longer. Therefore, considering all factors, the etchant formulations used in Experimental Groups 1 and 2 showed the best etching effect on the MoTi film.

[0032] Additionally, the electron microscope images of the etched samples from experimental groups 1 and 3 are as follows: Figure 1 and Figure 2 As shown in the figure (1 is CD bias; 2 is Tail; 3 is Tip; 4 is T / A), the addition of C-CHDC and ABF at a specific ratio can effectively ensure a low T / A value.

[0033] 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 MoTi film layer composite etchant composition, characterized by, The composition comprises the following raw materials in the indicated mass percentages: hydrogen peroxide 10.0%-12.0%, ammonium bifluoride 0.05%-0.1%, weak organic acid 4.0%-5.0%, corrosion inhibitor 0.5%-1.5%, cis-1,4-cyclohexanedicarboxylic acid 0.2%-0.5%, 3-amino-1,2,4-triazole 0.3%-0.5%, complexing agent 0.4%-0.6%, iminodiacetic acid 1.5%-2.5%, organic alcohol 2.0%-3.0%, and water to make up to 100%; and the ratio of ammonium bifluoride to cis-1,4-cyclohexanedicarboxylic acid is ≥0.

2. The complexing agent is obtained by mixing tetrasodium iminodisuccinate and sodium glutamate in a mass ratio of 6-8:

1. The weak organic acid is any one or a combination of citric acid, salicylic acid, tartaric acid, lactic acid, and acetic acid. The corrosion inhibitor is triethanolamine; The organic alcohol is at least one of polyether diol, butanediol, and triethylene glycol.

2. The etchant composition of claim 1, wherein: The etchant composition is used by spraying at a pressure of 0.1-0.2 MPa and an etching temperature of 25-35°C. During etching, the etching time is controlled to be extended by 50%-70% for over-etching.

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