Copper-based composite metal display etching solution as well as preparation method and application thereof

Abstract

The invention relates to a copper-based composite metal display etching solution and a preparation method and application thereof. The etching liquid comprises the following components in parts by weight: 5-20 parts of hydrogen peroxide; 5-15 parts of an acidic material; 0.01 to 0.05 part of a chelating agent; 2 to 10 parts of alcohol amine; 0.1-1 part of a corrosion inhibitor; 0.1-2 parts of a stabilizer; and 50 to 80 parts of deionized water. The chelating agent in the etching solution can strongly complex copper ions, so that decomposition of hydrogen peroxide is weakened, and a stable acid environment can be provided. The etching solution provided by the invention can ensure that the content of copper ions reaches 12,000 ppm, and in an etching reaction, a glass substrate does not have metal residues, two-section angles and Mo trailing phenomena. The etching solution disclosed by the invention can be applied to a Cu / MoNb alloy substrate and has a good etching effect.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor manufacturing technology, and in particular relates to a copper-based composite metal display etching solution and a preparation method and application thereof. Background Art

[0002] Metal etching is a technology that uses wet etching and dry etching to remove metal from the surface by chemical reaction or physical friction. Usually, metal etching can also be called photochemical metal etching. After exposure and development, the protective film of the area to be etched is removed. When the metal contacts the etching solution, the chemical reaction of the etching solution dissolves and corrodes the metal surface, thereby forming a concave or hollowed-out effect. Compared with aluminum-chromium wiring, the copper alloy used for the gate and data metal wiring of large displays has the advantages of low impedance, high mechanical strength, better resistance to electromigration and no environmental problems. However, copper has poor adhesion to glass substrates and insulating films and is easily diffused into silicon oxide films, so titanium, molybdenum, etc. are usually used as the underlying thin film metal.

[0003] The etching reaction of copper-based composite metal etching liquid requires three steps: the first step is metal oxidation process, the second step is dissolution, and the third step is chelation of metal ions. Among them, the main factor affecting the etching rate is the metal oxidation process. Since the oxidizing property of hydrogen peroxide is higher than that of monovalent copper ions (Cu + ) and copper (Cu), plus Cu 2+ It has a catalytic effect on the decomposition of hydrogen peroxide, so there are side reactions in the whole reaction: copper ions catalyze the decomposition of hydrogen peroxide, copper is oxidized by copper ions, and monovalent copper ions (Cu + ) is oxidized. During the copper etching reaction, hydrogen peroxide is continuously consumed and the concentration is continuously reduced.

[0004] As the reaction proceeds, the concentration of copper ions in the etching solution continues to increase. On the one hand, it catalyzes the decomposition of hydrogen peroxide. On the other hand, copper ions oxidize copper to generate cuprous ions under acidic conditions, which consume hydrogen peroxide in the etching solution, causing the Taper angle to continue to increase, and ultimately leading to a decrease in product yield. Therefore, in the acidic environment of copper etching solution, it is necessary to develop an etching solution that can quickly chelate copper ions as the amount of dissolved copper increases to form a stable chelate and will not crystallize. Summary of the invention

[0005] The technical problem solved by the present invention is that copper ions oxidize copper element under acidic conditions to generate cuprous ions, which consume hydrogen peroxide in the etching solution, causing the Taper angle to increase continuously, and ultimately causing the product yield to decrease.

[0006] In view of the technical problems existing in the prior art, the present invention designs a copper-based composite metal display etching solution and its preparation method and application. The etching solution of the present invention has a copper acid etching solution with super strong chelation of copper ions, and with the increase of the amount of dissolved copper, the hydrogen peroxide content is stable, and the etching rate is also stable. The etching solution has a high copper ion loading capacity and a long service life. The copper ion chelation in the etching solution is stable and the chelate will not crystallize and precipitate, the hydrogen peroxide decreases steadily with the increase of the amount of dissolved copper, and no two-stage angle phenomenon occurs in the reaction.

[0007] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising" and similar meanings, and closed-ended "consisting of..." and similar meanings.

[0008] In order to solve the above-mentioned technical problems, the present invention adopts the following solutions:

[0009] A copper-based composite metal display etching solution, characterized in that it comprises the following components calculated by weight:

[0010]

[0011] Furthermore, the chelating agent is one or more of trifucosyl-p-lacto-N-hexaose, lacto-N-difucotetraose, monofucosyl-p-lacto-N-tetrahexaose, and lacto-N-fucopentose II.

[0012] Furthermore, the stabilizer is one or more of 5-amino-4-methoxy-2-nitrobenzenesulfonic acid, 2,5-diaminobenzenesulfonic acid, and aminobenzenesulfonic acid.

[0013] Furthermore, the acidic substance is one or more of citric acid, cinnamic acid, oxalic acid, glycine, benzoic acid, p-toluic acid, o-toluic acid, p-aminobenzoic acid, o-aminobenzoic acid, aminotrimethylenephosphoric acid, and iminodisuccinic acid.

[0014] Further, the acidic substance is a mixture of citric acid and benzoic acid;

[0015] The mass ratio of the citric acid to the benzoic acid is (1-5):(1-3).

[0016] Furthermore, the alcoholamine is one or more of isopropanolamine, isobutanolamine, triethanolamine, and N,N-dimethylethanolamine.

[0017] Furthermore, the corrosion inhibitor is one or more of benzotriazole, 2-mercaptobenzothiazole, mercaptobenzotriazole, toluenetriazole, 3-aminotriazole, 5-aminotetrazolyl, 6-nitrobenzimidazole, 2-aminothiazole, 4-aminotetrazolyl, and 3-amino-1,2,4-triazole.

[0018] The present invention also discloses a method for preparing the copper-based composite metal display etching solution, which is characterized by comprising the following steps:

[0019] The components are weighed in proportion, mixed and stirred evenly, and filtered to obtain the copper-based composite metal display etching solution.

[0020] The present invention also discloses an etching method of the copper-based composite metal display etching solution, which is characterized by comprising the following steps:

[0021] Step 1: Immerse the glass substrate in the above etching solution and heat it to 31-35°C, and start timing;

[0022] Step 2: Rinse the etched glass substrate in ultrapure water for 30 seconds and blow dry with nitrogen.

[0023] The invention also discloses a use of the copper-based composite metal display etching solution in etching a glass substrate.

[0024] In the present invention, in order to further optimize the effect of the etching solution, the various components can be optimized: 10-20 parts of hydrogen peroxide; 5-10 parts of acidic substances; 0.01-0.04 parts of chelating agents; 4-10 parts of alcohol amines; 0.1-0.8 parts of corrosion inhibitors; 0.1-1 parts of stabilizers; and 60-80 parts of deionized water.

[0025] In the present invention, the chelating agent is preferably trifucosyl-p-lacto-N-hexaose.

[0026] In the present invention, the stabilizer is preferably 5-amino-4-methoxy-2-nitrobenzenesulfonic acid.

[0027] In the present invention, the mass ratio of the chelating agent to the stabilizer is preferably 1:(10-50), and the mass ratio of the chelating agent to the stabilizer may be further preferably 1:33.3.

[0028] In the present invention, the mass ratio of citric acid to benzoic acid is preferably 1:(1-3).

[0029] In the present invention, the alcoholamine is preferably N,N-dimethylethanolamine.

[0030] In the present invention, the corrosion inhibitor is preferably 6-nitrobenzimidazole or 2-aminothiazole.

[0031] In the present invention, the acidic substance not only provides an ultra-stable acidic environment for the etching reaction, but also converts the metal into ionic form to facilitate the subsequent chelating reaction, and can also stabilize the pH of the etching solution, making the etching reaction safer and preventing the risk of sudden boiling.

[0032] In the present invention, the chelating agent can chelate metal ions well, thereby stabilizing the hydrogen peroxide content of the etching solution, thereby weakening the decomposition of hydrogen peroxide by copper ions, stabilizing the pH of the etching solution, making the etching reaction safer, and preventing Cu in the etching solution from 2+ The increase in content causes the hydrogen peroxide content in the etching solution to be unstable and decompose rapidly, which in turn causes the etching solution temperature to rise sharply to 70°C, causing the liquid to boil and sudden boiling to occur.

[0033] In the present invention, the chelating agent can not only chelate copper ions, but also resist oxidation and scavenge free radical reactions. The mechanism is:

[0034] The chelating agent of the specific structure of the present invention has multiple hydroxyl groups, and the oxygen atoms on the hydroxyl groups bind to Cu 2+ The chelate produced after coordination can inhibit the free radical oxidation reaction of hydrogen peroxide decomposition.

[0035] Hydrogen peroxide will produce active free radicals (HO.2) during the decomposition process. The rate at which HO.2 reacts to generate O2 determines the rate at which H2O2 decomposes.

[0036] According to the "collision theory", when the temperature and copper ion concentration are constant, the entire reaction depends on the amount of active free radicals HO.2. To inhibit the decomposition of hydrogen peroxide, it is necessary to reduce the amount of HO.2, that is, to reduce the activity of HO.2.

[0037] Structurally, the structure of HO.2 is .OOH. Under the influence of external factors, its OH bond is easily broken to form O2 and H. If compounds containing strongly negative O and N atoms are added, these negative atoms will form hydrogen bonds with hydrogen, and the electron cloud on .OO will shift toward OH, thereby strengthening the OH bond and reducing the activity of (HO.2).

[0038] Therefore, the chelating agent can not only chelate copper ions, but also resist oxidation and scavenge free radical reactions, thereby maintaining the stability of the etching solution in the etching reaction.

[0039] In the present invention, the amino group and sulfonic acid group in the stabilizer have strongly negative nitrogen atoms and oxygen atoms, and do not occur or have no steric hindrance with other groups, which can inhibit free radical reactions, super-chelate metal ions, and thus prevent rapid decomposition of hydrogen peroxide.

[0040] The present invention provides a copper-based composite metal display etching solution and a preparation method and application thereof, which have the following beneficial effects:

[0041] 1. The chelating agent in the etching solution of the present invention can strongly complex copper ions, which not only weakens the decomposition of hydrogen peroxide, but also provides a stable acidic environment.

[0042] 2. The etching solution of the present invention can ensure that the copper ion content reaches 12000ppm, and during the etching reaction, there is no metal residue on the glass substrate, and no second-stage corner and Mo tailing phenomenon occurs.

[0043] 3. The etching solution of the present invention can be applied to Cu / MoNb alloy substrates (Cu layer thickness The thickness of the MoNb layer is ), has good etching effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 :For etching using Example 1 SEM image of glass substrate magnified 40,000 times after Cu / MoNb film thickness 500ppm;

[0045] Figure 2 :For etching using Example 1 SEM image of glass substrate magnified 40,000 times after Cu / MoNb film thickness 12,000ppm;

[0046] Figure 3 : For etching using Comparative Example 1 SEM image of glass substrate magnified 40,000 times after Cu / MoNb film thickness 500ppm. DETAILED DESCRIPTION

[0047] The present invention will be further described below in conjunction with specific embodiments and accompanying drawings:

[0048] Table 1 Example 1-Example 6

[0049]

[0050]

[0051] Table 2 Comparative Example 1-Comparative Example 2

[0052]

[0053]

[0054] Table 3 Test data

[0055]

[0056] About the preparation method of the etching solution of the present invention:

[0057] The present invention relates to the preparation of multiple groups of etching solutions, and the preparation methods thereof are all prepared by referring to the following method:

[0058] The components are weighed in proportion, mixed and stirred evenly to obtain the copper-based composite metal display etching solution.

[0059] About etching method:

[0060] Step 1: Immerse the glass substrate in the above etching solution and heat it to 32°C, then start timing;

[0061] Step 2: Rinse the etched glass substrate in ultrapure water for 30 seconds and blow dry with nitrogen.

[0062] About performance testing and description:

[0063] Performance 1 Taper angle and two-stage angle phenomenon:

[0064] Place the Cu / MoNb glass substrate into the prepared etching solution, control the etching reaction temperature between 31-35°C, conduct a long-term copper dissolution test (500-12000ppm), increase the copper content by 800ppm per hour, wait for the copper powder to dissolve completely in each stage, then place the glass substrate into the etching solution at 32°C for reaction, wait for all reactions to be completed, and send the etched glass substrate to SEM for inspection to observe the etching characteristics.

[0065] Performance 2H2O2 attenuation and pH increase:

[0066] In the 500-12000ppm continuous copper dissolution experiment, the H2O2 content and pH value of the etching solution are measured every 2000ppm. The calculation method is as follows:

[0067] H2O2 decay rate = (initial amount of hydrogen peroxide - final amount of hydrogen peroxide) / initial amount of hydrogen peroxide * 100%

[0068] pH increase = final pH value - initial pH value

[0069] Analysis of the test results:

[0070] In Comparative Example 1, due to the lack of the addition of the chelating agent trifucosyl-p-lacto-N-hexaose, as the copper ion content increases subsequently, the divalent copper ions cannot be chelated, so the hydrogen peroxide content decreases sharply, affecting the stability of the etching solution.

[0071] In Comparative Example 2, due to the lack of the addition of the stabilizer 5-amino-4-methoxy-2-nitrobenzenesulfonic acid, the amino and sulfonic acid groups in the stabilizer have strongly negative nitrogen atoms and oxygen atoms, and no steric hindrance occurs between them or occurs with other groups, which can inhibit free radical reactions. Therefore, the subsequent HO.2 amount continues to increase, resulting in the instability of hydrogen peroxide, affecting the etching effect.

[0072] After etching with the etching solution of the embodiment of the present invention, there is no second-stage corner, no Mo tailing is generated, and the etching effect is good.

[0073] In the determination of H2O2 attenuation and pH value change, it can be seen that the decrease in H2O2 content is stable and the pH value is stable.

[0074] Further comparison is made through the attached drawings in the specification:

[0075] Figure 1 :For etching using Example 1 SEM image of glass substrate magnified 40,000 times after Cu / MoNb film thickness 500ppm;

[0076] from Figure 1 It can be seen that there is no second angle and no Mo tailing after etching, indicating that the etching effect is good.

[0077] Figure 2 For etching using Example 1 SEM image of glass substrate with Cu / MoNb film thickness of 12000ppm, magnified 40000 times. Figure 2 It can be seen that there is no second angle and no Mo tailing after etching, indicating that the etching effect is good.

[0078] Figure 3 For etching using Comparative Example 1 SEM image of glass substrate with Cu / MoNb film thickness of 500ppm, magnified 40000 times. Figure 3 It can be seen that the glass substrate has obvious two-segment corners after etching.

[0079] The chelating agent in the etching solution of the present invention can strongly complex copper ions, not only weaken the decomposition of hydrogen peroxide, but also provide a stable acidic environment. The etching solution of the present invention can ensure that the copper ion content reaches 12000ppm, and during the etching reaction, there is no metal residue on the glass substrate, and no second-stage corner and Mo tailing phenomenon occurs. The etching solution of the present invention can be applied to Cu / MoNb alloy substrates and has a good etching effect.

[0080] The present invention is described exemplarily above in conjunction with the embodiments and drawings. It is obvious that the implementation of the present invention is not limited to the above-mentioned methods. As long as various improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A copper-based composite metal display etching solution, characterized in that: Calculated by weight, it includes the following components: 5-20 parts of hydrogen peroxide; 5-15 parts of acidic substances; Chelating agent 0.01-0.05 part; 2-10 parts of alcoholamine; Corrosion inhibitor 0.1-1 part; Stabilizer 0.1-2 parts; 50-80 parts of deionized water.

2. The copper-based composite metal display etching solution according to claim 1, characterized in that: The chelating agent is one or more of trifucosyl-p-lacto-N-hexaose, lacto-N-difucotetraose, monofucosyl-p-lacto-N-tetrahexaose, and lacto-N-fucopentose II.

3. The copper-based composite metal display etching solution according to claim 1, characterized in that: The stabilizer is one or more of 5-amino-4-methoxy-2-nitrobenzenesulfonic acid, 2,5-diaminobenzenesulfonic acid and aminobenzenesulfonic acid.

4. The copper-based composite metal display etching solution according to claim 1, characterized in that: The acidic substance is one or more of citric acid, cinnamic acid, oxalic acid, glycine, benzoic acid, p-toluic acid, o-toluic acid, p-aminobenzoic acid, o-aminobenzoic acid, aminotrimethylenephosphoric acid, and iminodisuccinic acid.

5. The copper-based composite metal display etching solution according to claim 4, characterized in that: The acidic substance is a mixture of citric acid and benzoic acid; The mass ratio of the citric acid to the benzoic acid is (1-5):(1-3).

6. The copper-based composite metal display etching solution according to claim 1, characterized in that: The alcohol amine is one or more of isopropanolamine, isobutanolamine, triethanolamine and N,N-dimethylethanolamine.

7. The copper-based composite metal display etching solution according to claim 1, characterized in that: The corrosion inhibitor is one or more of benzotriazole, 2-mercaptobenzothiazole, mercaptobenzotriazole, toluenetriazole, 3-aminotriazole, 5-aminotetrazolyl, 6-nitrobenzimidazole, 2-aminothiazole, 4-aminotetrazolyl, and 3-amino-1,2,4-triazole.

8. A method for preparing the copper-based composite metal display etching solution according to any one of claims 1 to 7, characterized in that The following steps are involved: The components are weighed in proportion, mixed and stirred evenly, and filtered to obtain the copper-based composite metal display etching solution.

9. An etching method for a copper-based composite metal display etching solution according to any one of claims 1 to 7, characterized in that The following steps are involved: Step 1: Immerse the glass substrate in the above etching solution and heat it to 31-35°C, and start timing; Step 2: Rinse the etched glass substrate in ultrapure water and blow dry with nitrogen.

10. Use of the copper-based composite metal display etching solution according to any one of claims 1 to 7 in etching a glass substrate.

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