Microelectronic metal layer etching solution and preparation method and application thereof

Abstract

The invention relates to a microelectronic metal layer etching solution which comprises the following components in parts by weight: 0.5-1 part of organic acid; 60-70 parts of inorganic acid; 10-20 parts of an organic solvent; 1-2 parts of an oxidant; 0.5-1 part of a functional agent; and 30-40 parts of ultrapure water. The invention also discloses a preparation method and application of the etching solution. The organic acid and the inorganic acid can form leaf-shaped molecules in water, and then the leaf-shaped molecules are mutually crosslinked with the functional agent and adsorbed on the metal surface through benzene rings, so that the etching rate of a titanium metal layer is ensured, the etching speed of fluorine ions on an aluminum metal layer is reduced, and a good lateral etching morphology is formed.

Description

Technical Field

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

[0002] In recent years, Micro-LEDs have become a research hotspot in the display field, attracting widespread attention worldwide. Recently, a monolithic Micro-LED display technology has been developed, which combines a micron-scale Si-based Micro-LED array with a high-efficiency CMOS driver backplane wafer via an inverted structure, achieving wafer-level optoelectronic heterogeneous integration. While achieving full-color monolithic Micro-LED displays remains to be achieved, monochromatic blue or green monolithic Micro-LED array chips have been developed, and these monochromatic Micro-LED display chips hold broad application prospects. The manufacturing process for monochromatic Micro-LED display chips typically involves depositing a multilayer Ti / Al / Ti metal layer on the substrate.

[0003] Etching is a crucial step in the production of monochrome, monolithic Micro-LED display chips. However, the significant differences in the chemical properties of titanium and aluminum lead to a mismatch in the etching rates of the titanium and aluminum films in the etching solution. To meet the requirements of subsequent processes, the wet etching of the titanium, aluminum, and titanium layers must avoid protrusions of the Ti layer at the top and bottom of the etching process, and the critical dimension loss of the metal must be appropriate.

[0004] Therefore, it is necessary to develop an etching solution that can be used for titanium-aluminum-titanium three-layer metal etching, and to ensure that the protrusion of the top and bottom Ti layers is reduced or even avoided after etching, and the critical size loss of the metal is small. Summary of the Invention

[0005] The technical problem solved by the present invention is that when wet etching the titanium, aluminum and titanium three layers, the top and bottom Ti layers protrude after etching, resulting in a large loss of metal critical size.

[0006] In view of the technical problems existing in the prior art, the present invention provides an etching solution for a Ti / Al / Ti substrate and a preparation method thereof, which can reduce or even avoid the occurrence of protrusions in the top and bottom Ti layers, and ensure that the critical dimension loss of the metal after etching is small. It should be noted that in the present invention, unless otherwise specified, the specific meaning of "including" in the definition and description of composition includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "consisting of", etc. and similar meanings.

[0007] In order to solve the above-mentioned technical problems, the present invention adopts the following solutions:

[0008] A microelectronic metal layer etching solution, characterized in that it comprises the following components, calculated in parts by weight:

[0009]

[0010] The functional agent is a fluorine-containing organic compound.

[0011] Furthermore, the functional agent is one or more of 4-(4-(3-(4-chloro-3-(trifluoromethyl)phenyl)ureido)phenoxy)-N-methyl-2-pyridinecarboxamide, N-(2-aminoethyl)-4-[4-[3-[4-chloro-3-(trifluoromethyl)phenyl]ureido]phenoxy]pyridine-2-carboxamide, o-chlorobenzotrifluoride, and 2-chloro-4-methylbenzotrifluoride.

[0012] Furthermore, the organic acid is one or more of 2-anthraquinonesulfonic acid, sulfonic acid, 2-butylsulfonic acid, and propanesulfonic acid.

[0013] Furthermore, the inorganic acid is nitric acid and / or hydrochloric acid.

[0014] Furthermore, the organic solvent is one or more of propylene glycol, ethanol, dimethyl sulfoxide, and diethyl sulfoxide.

[0015] Furthermore, the oxidant is peroxydodecanoic acid and / or diperoxysebacic acid.

[0016] Furthermore, the ultrapure water is deionized water with a resistance of ≥18 MΩ.

[0017] The present invention also discloses a method for preparing a microelectronic metal layer etching solution, which is characterized by comprising the following steps:

[0018] Step 1: Add the functional agent and oxidant to the organic solvent at room temperature and stir evenly;

[0019] Step 2: Add organic acid and inorganic acid to ultrapure water at room temperature and stir evenly;

[0020] Step 3: Add the solution prepared in step 1 to the solution prepared in step 2 at room temperature and stir evenly to obtain an etching solution.

[0021] The present invention also discloses a method for using a microelectronic metal layer etching solution, which is characterized by comprising the following steps:

[0022] The Ti / Al / Ti substrate is placed in an etching solution and etched at 20-40° C. for 50-150 seconds. After the etching is completed, the Ti / Al / Ti substrate is rinsed and dried to obtain an etched substrate.

[0023] The invention also discloses application of a microelectronic metal layer etching solution in the preparation of a Ti / Al / Ti substrate.

[0024] In the etching solution system of the present invention, in order to further optimize the effect, each component can be optimized, 0.8-1 parts of organic acid; 65-70 parts of inorganic acid; 13-16 parts of organic solvent; 1.4-1.8 parts of oxidant; 0.7-0.9 parts of functional agent; and 32-38 parts of ultrapure water.

[0025] In the present invention, the functional agent is 4-(4-(3-(4-chloro-3-(trifluoromethyl)phenyl)ureido)phenoxy)-N-methyl-2-pyridinecarboxamide.

[0026] In the present invention, the organic acid is 2-anthraquinonesulfonic acid.

[0027] In the present invention, the inorganic acid is hydrochloric acid.

[0028] In the present invention, the organic solvent is ethanol.

[0029] In the present invention, the oxidizing agent is peroxydodecanoic acid.

[0030] In the present invention, the mixing and stirring time in step 1 of the method for preparing the etching solution is 10-30 minutes.

[0031] In the present invention, the mixing and stirring time in step 2 of the method for preparing the etching solution is 20-30 minutes.

[0032] In the present invention, the mixing and stirring time in step 3 of the method for preparing the etching solution is 10-30 minutes.

[0033] In the present invention, the etching time in the method of using the etching solution is 80-110 seconds.

[0034] The present invention provides a microelectronic metal layer etching solution and its preparation method and application, which have the following beneficial effects:

[0035] 1. The organic acid and inorganic acid of the present invention can form leaf-like crystals in water and dissolve in organic solvents to maintain leaf-like molecules. After cross-linking with the functional agent, they are adsorbed on the metal surface with benzene rings, ensuring the etching rate of the titanium metal layer and reducing the etching of the aluminum metal layer by F ions, thereby forming a good side etching morphology.

[0036] 2. The oxidant of the present invention is preferably peroxydodecanoic acid, which can be grafted onto the leaf-shaped molecules formed by organic acid and inorganic acid, so that the titanium metal layer is etched evenly. The oxidant gradually decomposes after etching the titanium metal layer, further reducing the etching of the aluminum metal layer.

[0037] Therefore, the etching solution of the present invention has very good application prospects and large-scale industrial promotion potential in the field of semiconductor chip etching. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 :After etching using the etching solution of Example 1 / / SEM image of the side etching of the Ti / Al / Ti substrate at 40,000x magnification.

[0039] Figure 2 :After etching using the etching solution of Comparative Example 1 / / SEM image of the side etching of the Ti / Al / Ti substrate at 40,000x magnification. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0041] Table 1 Examples 1-8

[0042]

[0043]

[0044] Table 2 Comparative Examples 1-4

[0045]

[0046] Table 3 Test data

[0047]

[0048]

[0049] The method for preparing the microelectronic metal layer etching solution of the present invention comprises the following steps:

[0050] Step 1: Add the functional agent and oxidant to the organic solvent and stir for 20 minutes;

[0051] Step 2: Add organic acid and inorganic acid to ultrapure water and stir for 24 minutes;

[0052] Step 3: Add the solution prepared in step 1 to the solution prepared in step 2 and stir for 18 minutes to obtain an etching solution.

[0053] The method for using the microelectronic metal layer etching solution of the present invention comprises the following steps:

[0054] Step 1: Immerse the Ti / Al / Ti substrate in an etching solution for etching; the etching time is 100 seconds and the etching temperature is 25°C.

[0055] Step 2: Rinse the Ti / Al / Ti substrate in ultrapure water at least twice and blow dry with nitrogen.

[0056] The ultrapure water used in the present invention is deionized water with a resistance of at least 18 MΩ.

[0057] About performance testing and description:

[0058] The test method for the morphology after performance etching and the protrusion of the Ti layer is:

[0059] The Ti / Al / Ti samples were etched using the etching solutions of the above embodiments and comparative examples of the present invention, and then cleaned after etching. The specific steps are as follows:

[0060] Step 1: Immerse the Ti / Al / Ti substrate in an etching solution for etching; the etching time is 100 seconds and the etching temperature is 25°C.

[0061] Step 2: Rinse the Ti / Al / Ti substrate in ultrapure water at least twice and blow dry with nitrogen.

[0062] Step 3: Observe the sample morphology under SEM. The protrusion of the Ti layer can be calculated by measuring the difference between the top Ti layer and the underlying Al layer.

[0063] The ultrapure water used in the above steps is deionized water with a resistance of at least 18 MΩ.

[0064] Analysis of the test results:

[0065] It can be seen from the test data in Table 3 that the etching solution of the embodiment has a good morphology after etching and maintains a low top Ti protrusion. However, since the organic acid in Comparative Example 1 is citric acid, it cannot form a cross-linked state with the functional agent, affecting the morphology of the Al layer after etching; Comparative Example 2 lacks peroxydodecanoic acid, resulting in fluoride ions freely attacking the Ti layer, resulting in uneven etching; Comparative Example 3 lacks 4-(4-(3-(4-chloro-3-(trifluoromethyl)phenyl)ureido)phenoxy)-N-methyl-2-pyridinecarboxamide, resulting in no fluoride ions in the solution and the Ti layer cannot be etched; Comparative Example 4 uses ammonium fluoride as the functional agent, and the fluoride ions are insufficiently in contact with the Ti layer, resulting in a top Ti protrusion.

[0066] Further comparison is made through the accompanying drawings in the specification:

[0067] Figure 1 After etching using the etching solution of Example 1 / / SEM image of the side etching of the Ti / Al / Ti substrate at 40,000x magnification. Figure 2 After etching using the etching solution of Comparative Example 1 / / SEM image of the side etching of the Ti / Al / Ti substrate at 40,000x magnification.

[0068] Figure 1 and Figure 2 The data in the figure is the difference between the top Ti layer and the Al layer below. Figure 1 and Figure 2 By comparison, it can be proved that the top Ti layer protrudes obviously after etching with the etching solution of Comparative Example 1, while the top Ti layer does not protrude after etching with the etching solution of Example 1.

[0069] The present invention has been described above by way of example in conjunction with the embodiments and accompanying 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 concepts and technical solutions of the present invention, or the concepts and technical solutions of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A microelectronic metal layer etching solution, characterized in that: Calculated by weight, it includes the following components: 0.5-1 part of organic acid; 60-70 parts of inorganic acid; 10-20 parts of organic solvent; 1-2 parts of oxidant; Functional agent 0.5-1 part; 30-40 parts of ultrapure water; The functional agent is a fluorine-containing organic compound.

2. The microelectronic metal layer etching solution according to claim 1, wherein: The functional agent is one or more of 4-(4-(3-(4-chloro-3-(trifluoromethyl)phenyl)ureido)phenoxy)-N-methyl-2-pyridinecarboxamide, N-(2-aminoethyl)-4-[4-[3-[4-chloro-3-(trifluoromethyl)phenyl]ureido]phenoxy]pyridine-2-carboxamide, o-chlorobenzotrifluoride, and 2-chloro-4-methylbenzotrifluoride.

3. The microelectronic metal layer etching solution according to claim 1, wherein: The organic acid is one or more of 2-anthraquinonesulfonic acid, sulfonic acid, 2-butylsulfonic acid and propanesulfonic acid.

4. The microelectronic metal layer etching solution according to claim 1, wherein: The inorganic acid is nitric acid and / or hydrochloric acid.

5. The microelectronic metal layer etching solution according to claim 1, wherein: The organic solvent is one or more of propylene glycol, ethanol, dimethyl sulfoxide and diethyl sulfoxide.

6. The microelectronic metal layer etching solution according to claim 1, wherein: The oxidant is peroxydodecanoic acid and / or diperoxysebacic acid.

7. The microelectronic metal layer etching solution according to claim 1, characterized in that: The ultrapure water is deionized water with a resistance of ≥18MΩ.

8. A method for preparing a microelectronic metal layer etching solution according to any one of claims 1 to 7, characterized in that The following steps are involved: Step 1: Add the functional agent and oxidant to the organic solvent at room temperature and stir evenly; Step 2: Add organic acid and inorganic acid to ultrapure water at room temperature and stir evenly; Step 3: Add the solution prepared in step 1 to the solution prepared in step 2 at room temperature and stir evenly to obtain an etching solution.

9. A method for using the microelectronic metal layer etching solution according to any one of claims 1 to 7, characterized in that The following steps are involved: The Ti / Al / Ti substrate is placed in an etching solution and etched at 20-40° C. for 50-150 seconds. After the etching is completed, the Ti / Al / Ti substrate is rinsed and dried to obtain an etched substrate.

10. Use of the microelectronic metal layer etching solution according to any one of claims 1 to 7 in the preparation of Ti / Al / Ti substrates.

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