F-free low-igzo damage metal etching solution and preparation method thereof

Abstract

The application provides a kind of F-free one-dose low IGZO damage metal etching solution and preparation method thereof, and relates to the technical field of semiconductor display panel manufacturing.The F-free one-dose low IGZO damage metal etching solution is composed of the following raw materials: hydrogen peroxide, complexing agent, 2,4-dichlorophenoxyacetic acid, ethylenediaminetetraacetic acid, corrosion inhibitor compound, and ultra-pure water is added to make up the volume;the corrosion inhibitor compound is obtained by mixing 2-mercapto-5-methylbenzimidazole and aminotrimethyl phosphonic acid in a mass ratio of 1:2-3, and the ratio of the addition amount of ethylenediaminetetraacetic acid to the corrosion inhibitor compound is ≤1.2.The application uses a complexing agent-corrosion inhibitor compound synergistic system, the IGZO layer damage rate is <5%, which significantly improves the device yield, and the Cu etching rate is 500-800 Å / min, the MoTi etching rate is 300-500 Å / min, and the rate matching is good.

Description

Technical Field

[0001] This invention relates to the field of semiconductor display panel manufacturing technology, specifically to an F-free, low-IGZO-damage metal etching solution and its preparation method. Background Technology

[0002] In display panel manufacturing, MTD / Cu / MoTi and MoTi / Cu / MoTi laminates are widely used for metal wiring due to their excellent conductivity and adhesion. However, traditional etching solutions used to form intricate circuit patterns in these laminates suffer from the following technical drawbacks:

[0003] 1. High fluoride content (usually >0.1%): Fluoride ions easily corrode the IGZO (indium gallium zinc oxide) layer, leading to a degradation of the device's electrical performance;

[0004] 2. H2O2 concentration is generally >30%: It is prone to excessive oxidation of the metal layer, and has poor stability and is easily decomposed;

[0005] 3. Improper selection of complexing and chelating agents: leading to the formation of metal ions (such as Cu). 2+ Mo 4+ Ti 4+ Insufficient complexation and mismatched etching rates can lead to a "roof" effect or over-etching.

[0006] 4. Insufficient corrosion inhibition effect: This results in high roughness and poor verticality of the metal layer sidewalls, affecting wiring accuracy. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention is achieved through the following technical solution:

[0008] A low-IGZO-damage metal etching solution without F-agent, comprising, by weight percentage: 5%-20% hydrogen peroxide (H2O2), 2%-4% complexing agent, 0.4%-1% 2,4-dichlorophenoxyacetic acid (C8H6Cl2O3), and 0.4%-1% ethylenediaminetetraacetic acid (C2H2O2). 10 H 16 Add 0.6%-2% N2O8, 0.5%-1.6% corrosion inhibitor compound, and make up to 100% with ultrapure water;

[0009] The corrosion inhibitor compound is 2-mercapto-5-methylbenzimidazole (C8H8N2S) and aminotrimethylphosphonic acid (C3H 12 The mixture of NO9P3 and ethylenediaminetetraacetic acid (EDTA) and corrosion inhibitor is prepared by mixing them at a mass ratio of 1:2-3, and the ratio of EDTA to corrosion inhibitor is ≤1.2.

[0010] Preferably, the complexing agent is triethylene glycol (C6H4O3). 14O4), ethylene glycol (C2H6O2), diethylene glycol (C4H) 10 Any one of O3).

[0011] The preparation steps of an etching solution preparation method are as follows:

[0012] S1. At room temperature, add ultrapure water to the container, and while stirring, add the complexing agent, 2,4-dichlorophenoxyacetic acid (C8H6Cl2O3), and ethylenediaminetetraacetic acid (C8H6Cl2O3). 10 H 16 N2O8), stir until completely dissolved to obtain mixture A;

[0013] S2. Add corrosion inhibitor to mixture A and continue stirring for 5-10 minutes to obtain mixture B.

[0014] S3. Add hydrogen peroxide dropwise to mixture B and stir continuously. After the addition is complete, continue stirring for 15-20 minutes to obtain the etching solution.

[0015] Preferably, the stirring speed in steps S1, S2, and S3 is 20-80 rpm.

[0016] Preferably, the hydrogen peroxide droplet acceleration in step S3 is 5-10 mL / min.

[0017] Preferably, the etching solution is used at a temperature of 25-45°C and the etching time is 30-180 seconds.

[0018] Preferably, the etching solution is used by spraying, and the spraying pressure is 0.1-0.3 MPa.

[0019] This invention provides a low-IGZO-damage metal etching solution without F-agent and its preparation method, which has the following advantages compared with the prior art:

[0020] This invention employs a complexing agent-corrosion inhibitor synergistic system, resulting in an IGZO layer damage rate of <5%, significantly improving device yield. Furthermore, the Cu etching rate is 500-800 Å / min, and the MoTi etching rate is 300-500 Å / min, demonstrating good rate matching.

[0021] This invention utilizes a corrosion inhibitor compounded from 2-mercapto-5-methylbenzimidazole and aminotrimethylphosphonic acid. Introducing phosphonic acid groups (-PO3H2) into 2-mercapto-5-methylbenzimidazole allows for strong chemical adsorption with the metal hydroxyl groups (-OH) on the IGZO surface, forming a dense, ordered self-assembled monolayer. This hydrophobic organic film effectively prevents direct contact between the etching solution and the IGZO, providing selective protection. Simultaneously, it accelerates the Cu etching rate, and the aminotrimethylphosphonic acid reacts with the Cu produced during etching. 2+It forms a soluble complex, preventing redeposition or passivation of copper on the surface, thereby maintaining the continuous dissolution of copper. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the test substrate structure and S / E value measurement;

[0023] Figure 2 SEM image of the test substrate after etching with etching solution N1;

[0024] Figure 3 This is a SEM image of the test substrate after etching with N2 etchant;

[0025] Figure 4 SEM image of the test substrate after etching with N3 etchant;

[0026] Figure 5 SEM image of the test substrate after etching with N4 etchant;

[0027] Figure 6 SEM image of the test substrate after etching with etching solution N5;

[0028] Figure 7 SEM image of the test substrate after etching with etching solution N6;

[0029] Figure 8 SEM image of the test substrate after etching with etching solution N7;

[0030] Figure 9 SEM image of the IGZO layer on the test substrate after etching with N1 etchant;

[0031] Figure 10 SEM image of the IGZO layer on the test substrate after etching with N2 etchant;

[0032] Figure 11 SEM image of the IGZO layer on the test substrate after etching with N3 etchant;

[0033] Figure 12 SEM image of the IGZO layer on the test substrate after etching with N4 etchant;

[0034] Figure 13 SEM image of the IGZO layer on the test substrate after etching with N5 etchant;

[0035] Figure 14 SEM image of the IGZO layer on the test substrate after etching with N6 etchant;

[0036] Figure 15 This is a SEM image of the IGZO layer on the test substrate after etching with N7 etchant. Detailed Implementation

[0037] 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.

[0038] Example:

[0039] The etching solution consists of the raw materials listed in Table 1 by weight percentage (the balance being ultrapure water):

[0040] Table 1

[0041]

[0042] Based on the raw material composition in the table above, the etching solution is prepared according to the following steps:

[0043] S1. Adjust the temperature to 23℃, add ultrapure water to the container, add triethylene glycol, 2,4-dichlorophenoxyacetic acid and ethylenediaminetetraacetic acid while stirring at 50 rpm, and stir at 50 rpm until completely dissolved to obtain mixture A;

[0044] S2. Add corrosion inhibitor to mixture A and continue stirring at 50 rpm for 8 minutes to obtain mixture B;

[0045] S3. Add hydrogen peroxide dropwise to mixture B at a rate of 7 ml / min while stirring continuously at a rate of 50 rpm. After the addition is complete, continue stirring for 18 min to obtain the etching solution.

[0046] Detection:

[0047] I. Etching verification materials:

[0048] The MoTi / Cu / MoTi and MTD (molybdenum nickel titanium alloy) / Cu / MoTi stacked structures were used as test substrates to verify the etching effects of each group of etching solutions on Cu, IGZO and MoTi.

[0049] II. Etching verification conditions:

[0050] The test substrate was subjected to spray etching with a spray pressure of 0.02 MPa, an etching temperature of 30°C, and an etching time of 140 seconds. After etching, it was rinsed with ultrapure water for 40 seconds and then dried with nitrogen.

[0051] III. Etching Experiment:

[0052] 1. Etching experiment for Cu:

[0053] The MTD / Cu / MoTi substrates were etched using the etching verification conditions described above with different etching solutions. After etching, the substrate etching was observed and the Cu-MTD S / E value of each substrate was recorded (S / E represents the lateral etching amount, e.g., ...). Figure 1 (As shown), the specific test results are as follows: Figure 2-8 (The reading "1" in the figure represents the measured "S / E value" in the table) and is shown in Table 2 below:

[0054] Table 2

[0055]

[0056] As can be seen from the table above, the addition of C8H6Cl2O3 can significantly improve the etching rate of the etchant on the test substrate (as shown by the control group 7). It can also be seen that when the slow-release compound is combined with C... 10 H 16 When the mass ratio of N2O8 is greater than 1.2 (experimental group 3), Figure 4 As shown in the figure, although the etching rate increased significantly, it was still less than the etching rate of experimental group 1.

[0057] 2. Etching experiments for MTD and MoTi:

[0058] Prepare MoTi / Cu / MoTi and MTD / Cu / MoTi substrates of the same specifications, measure the initial thickness, and etch the MoTi / Cu / MoTi and MTD / Cu / MoTi substrates with the etching solutions described above under the etching verification conditions. Measure the thickness after etching and calculate the etching rate of the MoTi and MTD layers. The specific results are shown in Table 3.

[0059] Table 3

[0060]

[0061] As shown in the table above, the N1 etching solution used in experimental group 7 had the best etching rate for the MTD layer and the MoTi layer.

[0062] 3. Etching experiments for IGZO:

[0063] The MTD / Cu / MoTi substrate was etched using the etching verification conditions described above with each group of etching solutions. The damage rate of the IGZO layer after etching was measured by SEM. The damage rate was calculated as shown in formula (1).

[0064] Damage rate of IGZO layer (%) = (left S / E value - right S / E value) / 1 * 100% (1)

[0065] The specific results are shown in Table 4 below:

[0066] Table 4

[0067]

[0068] As shown in the table above, the N1 etching solution used in experimental group 13 caused the least damage to the IGZO layer (e.g., Figure 9 As shown in Table 2, the N3 etching solution used in experimental group 15, although its etching rate is relatively fast based on the experimental data in Table 2, shows, in conjunction with Table 4, that it causes the most damage to the IGZO layer (combined with...). Figure 11 (As shown).

[0069] In summary, adding C8H6Cl2O3 to the etching solution can increase the etching rate of the test substrate, according to C 10 H 16 When N2O8 is prepared with a mass ratio of ≤1.2 to corrosion inhibitor, it can play a protective role for the IGZO layer.

[0070] 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 low-IGZO-damage metal etching solution without F-agent, characterized in that, The etching solution, by mass percentage, is composed of the following raw materials: 5%-20% hydrogen peroxide, 2%-4% complexing agent, 0.4%-1% 2,4-dichlorophenoxyacetic acid, 0.6%-2% ethylenediaminetetraacetic acid, 0.5%-1.6% corrosion inhibitor compound, and ultrapure water to make up to 100%; The corrosion inhibitor compound is obtained by mixing 2-mercapto-5-methylbenzimidazole and aminotrimethylphosphonic acid at a mass ratio of 1:2-3, and the mass ratio of ethylenediaminetetraacetic acid to the corrosion inhibitor compound is ≤1.

2.

2. The etching solution according to claim 1, characterized in that, The complexing agent is any one of triethylene glycol, ethylene glycol, and diethylene glycol.

3. A method for preparing the etching solution as described in any one of claims 1-2, characterized in that, The preparation steps of the etching solution are as follows: S1. At room temperature, add ultrapure water to a container, and while stirring, add complexing agent, 2,4-dichlorophenoxyacetic acid, and ethylenediaminetetraacetic acid. Stir until completely dissolved to obtain mixture A. S2. Add corrosion inhibitor to mixture A and continue stirring for 5-10 minutes to obtain mixture B. S3. Add hydrogen peroxide dropwise to mixture B and stir continuously. After the addition is complete, continue stirring for 15-20 minutes to obtain the etching solution.

4. The method for preparing the etching solution according to claim 3, characterized in that, The stirring speed in steps S1, S2, and S3 is 20-80 rpm.

5. The method for preparing the etching solution according to claim 3, characterized in that, The hydrogen peroxide droplet acceleration rate in step S3 is 5-10 mL / min.

6. The method for preparing the etching solution according to claim 3, characterized in that, The etching solution is used at a temperature of 25-45℃ and the etching time is 140s.

7. The method for preparing the etching solution according to claim 3, characterized in that, The etching solution is used by spraying, and the spraying pressure is 0.1-0.3 MPa.

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