A nitride semiconductor etching solution, a method for preparing the same, and use thereof

Abstract

The application provides a nitride semiconductor etching solution, a preparation method and application thereof, and the nitride semiconductor etching solution comprises the following components in a weight ratio: 1-20 parts of hydrogen peroxide; 1-10 parts of sodium salt; 5-40 parts of inorganic acid; 5-10 parts of organic acid; and 10-30 parts of ultrapure water. The sodium salt is one or more of sodium diethylenetriamine pentamethylene phosphonate, five sodium diethylenetriamine pentamethylene phosphonate and seven sodium diethylenetriamine pentamethylene phosphonate. The application further discloses a preparation method of the nitride semiconductor etching solution and application thereof in the field of nitride metal film etching. The nitride semiconductor etching solution can react with the nitride metal film, can inhibit the decomposition of hydrogen peroxide, and can prevent the metal ions after etching from being adsorbed to the surface of the substrate and from polluting the substrate.

Description

TECHNICAL FIELD

[0001] The present application relates to etching liquid technology, in particular to a nitride semiconductor etching liquid, its preparation method and use. BACKGROUND

[0002] Metal nitride such as titanium nitride (TiN) and the like can be generally applied in the fields of semiconductor devices, displays, micro-electro-mechanical system (MEMS) devices, printed wiring boards, etc., as a barrier layer to inhibit the etching of the underlying substrate, having the function of a protective film. The metal nitride layer is relatively difficult to remove by etching liquid, and is generally polished by the physical action of chemical mechanical polishing (CMP) to remove the metal nitride layer.

[0003] Some nitride etching liquids are currently disclosed, for example:

[0004] CN102149851A discloses an etching liquid for titanium-based metal, tungsten-based metal, titanium-tungsten-based metal or their nitrides, which contains hydrogen peroxide, organic acid salt and water. By using the etching liquid, uniform etching can be carried out.

[0005] KR1020180045185A discloses a metal nitride etchant composition, which contains peroxide, organic acid, organic acid salt and water, and can improve the etching selectivity ratio of a metal nitride layer containing tungsten (W).

[0006] CN111849486B discloses an etching composition and an etching method using the same, which comprises sulfuric acid, hydrogen peroxide, organic peroxide and water. The etching composition effectively controls the etching rate of the metal film, and can selectively etch the nitride metal film.

[0007] Although some nitride etching liquids are disclosed in the prior art, in the case of complex processes and CMP, the efficiency of the general wet process is low, which is limited in actual application, and there are problems such as the generation of other pollutants, high cost, etc. Therefore, it is necessary to develop a safe, environmentally friendly and efficient nitride semiconductor etching liquid, which can selectively etch the nitride metal film on polysilicon SiON, SiN. SUMMARY

[0008] The purpose of the present application is to solve the problems of low etching efficiency and easy pollution of pollutants to the substrate of the conventional nitride etching liquid, and to propose a nitride semiconductor etching liquid which can react with the nitride metal film and inhibit the decomposition of hydrogen peroxide, preventing the adsorption of metal ions on the surface of the substrate after etching, and polluting the substrate.

[0009] It should be noted that in the present application, unless otherwise specified, the specific meaning of "including" involved in the composition limitation and description includes both the open "including", "containing" and the like and the closed "consisting of" and the like.

[0010] To achieve the above object, the technical scheme adopted by the present application is: a nitride semiconductor etching solution comprising the following components in a weight ratio:

[0011]

[0012] Further, the concentration of the hydrogen peroxide is 1-20%. Unless otherwise specified, the % in the present application is the mass percentage.

[0013] Further, the concentration of the hydrogen peroxide is preferably 5-10%.

[0014] Further, the concentration of the hydrogen peroxide is most preferably 8%.

[0015] Further, the hydrogen peroxide is 5-10 parts.

[0016] Further, the sodium salt is one or more of sodium diethylenetriamine pentamethylene phosphonate, five sodium diethylenetriamine pentamethylene phosphonate and seven sodium diethylenetriamine pentamethylene phosphonate.

[0017] Further, the sodium salt is preferably sodium diethylenetriamine pentamethylene phosphonate.

[0018] Further, the mass ratio of the hydrogen peroxide and the sodium diethylenetriamine pentamethylene phosphonate is 4:1-1:4.

[0019] Further, the mass ratio of the hydrogen peroxide and the sodium diethylenetriamine pentamethylene phosphonate is preferably 2:1-1:2.

[0020] Further, the mass ratio of the hydrogen peroxide and the sodium diethylenetriamine pentamethylene phosphonate is more preferably 1.5:1.

[0021] Further, the sodium salt is 3-8 parts.

[0022] Further, the inorganic acid is selected from one or more of nitric acid, hydrofluoric acid, sulfuric acid and hydrochloric acid.

[0023] Further, the inorganic acid is preferably nitric acid and / or hydrofluoric acid.

[0024] Further, the inorganic acid is preferably nitric acid and hydrofluoric acid.

[0025] Further, the mass ratio of the nitric acid and the hydrofluoric acid is 1:1-1:10.

[0026] Further, the mass ratio of the nitric acid and the hydrofluoric acid is preferably 1:1-1:5.

[0027] Further, the mass ratio of the nitric acid and the hydrofluoric acid is more preferably 1:3.

[0028] Further, the inorganic acid is 10-30 parts.

[0029] Further, the organic acid is selected from one or more of formic acid, acetic acid, oxalic acid, lactic acid and citric acid.

[0030] Further, the organic acid is preferably acetic acid.

[0031] Further, the organic acid is 6-8 parts.

[0032] Further, the ultrapure water is 15-25 parts.

[0033] Further, the pH value of the nitride semiconductor etching solution is 3-5.

[0034] Further, the pH value of the nitride semiconductor etching solution is preferably 3.5-4.5.

[0035] Another object of the present application also discloses a preparation method of a nitride semiconductor etching solution, comprising the following steps:

[0036] Step 1: respectively weigh each component;

[0037] Step 2: first add ultrapure water, add hydrogen peroxide while stirring, then add inorganic acid, sodium salt, stir until completely dissolved, finally add organic acid, stir until uniform and transparent, and the nitride semiconductor etching solution is obtained.

[0038] Another object of the present application also discloses a use of a nitride semiconductor etching solution in the field of etching of nitride metal films.

[0039] Another object of the present application also discloses a method for etching a nitride metal film by using a nitride semiconductor etching solution, comprising the following steps: diluting the etching solution of the nitride metal film with ultrapure water to 50-80 times, then soaking the substrate at 30-50℃ for 1-5h, and the etching of the nitride metal film is completed.

[0040] Further, the substrate is soaked at 35-45℃ for 1h.

[0041] Further, the etched substrate is rinsed in ultrapure water for two to three times, and the cleaning after the etching of the nitride metal film is completed.

[0042] Further, the surface moisture of the cleaned substrate is absorbed by dust-free paper to avoid the influence of water on the corrosion of the metal surface.

[0043] The nitride semiconductor etching solution can selectively etch the nitride metal film on the polysilicon SiON and SiN, and is used in the field of semiconductor and display panel manufacturing. Specifically, the nitride semiconductor etching solution has the following advantages compared with the prior art:

[0044] 1. The nitride semiconductor etching solution contains sodium salt, especially sodium diethylenetriamine penta(methylene phosphonate) with weak acidity, which can be used as a metal corrosion inhibitor. When used with hydrogen peroxide at a specific ratio, the etching effect is better, and the etching reaction with the nitride metal film can be controlled accurately. At the same time, it can inhibit the decomposition of hydrogen peroxide and prevent the adsorption of metal ions on the substrate surface after etching, thereby preventing the pollution of the substrate.

[0045] 2. The viscosity of the nitride semiconductor etching solution is less than 10 Pa·s, which can be easily cleaned and can avoid the problem of residual etching solution after cleaning.

[0046] 3. The nitride semiconductor etching method is simple and does not require high-temperature soaking. The etching solution can be cleaned with ultrapure water during cleaning after etching.

[0047] Therefore, the nitride semiconductor etching solution has very good application prospects and large-scale industrialization potential in the field of semiconductors. BRIEF DESCRIPTION OF DRAWINGS

[0048] Fig. 1 is an optical microscope photo of the nitride metal film etched by the etching solution of Comparative Example 1, magnified by 200 times in bright field;

[0049] Fig. 2 is an optical microscope photo of the nitride metal film etched by the etching solution of Example 1, magnified by 200 times in bright field;

[0050] Fig. 3 is an optical microscope photo of the nitride metal film etched by the etching solution of Comparative Example 1 (left) and Example 1 (right), magnified by 200 times in dark field. DETAILED DESCRIPTION

[0051] The application is further described below in conjunction with examples:

[0052] Examples 1-12

[0053] This example discloses a variety of nitride semiconductor etching solutions, which contain the components and weight ratios as shown in Table 1. The preparation method of the nitride semiconductor etching solution comprises the following steps: weighing each component according to Table 1; first adding ultrapure water, then adding hydrogen peroxide while stirring, then adding inorganic acid and sodium salt, stirring until completely dissolved, and finally adding organic acid, stirring until uniform and transparent, to obtain the nitride semiconductor etching solution.

[0054] Table 1 Composition and weight ratio of nitride semiconductor etching solution of Examples 1-12

[0055]

[0056]

[0057] Comparative Examples 1-4

[0058] Comparative Examples 1-4 disclose various nitride semiconductor etching solutions, which contain components and weight ratios as shown in Table 2. The preparation method of the nitride semiconductor etching solution is the same as that of Example 1.

[0059] Table 2 Composition and weight ratio of nitride semiconductor etching solution of Comparative Examples 1-4

[0060]

[0061] Performance test and explanation

[0062] The various performances of the above examples or comparative examples were tested as follows, and the test results are shown in Table 3. The etching solution of Examples 1-12 has a high etching rate, can maintain effectiveness for a long time, has no residue after etching, and has no damage to the metal; while the etching solution of Comparative Examples 1-4 has a low etching rate, a short service life, has residue after etching, and has damage to the metal.

[0063] Table 3 Performance test results

[0064]

[0065] Fig. 1 is a 200x bright field optical microscope photograph of the nitride metal film etched using the etching solution of Comparative Example 1; Fig. 2 is a 200x bright field optical microscope photograph of the nitride metal film etched using the etching solution of Example 1; Fig. 3 is a 200x dark field optical microscope photograph of the nitride metal film etched using Comparative Example 1 (left) and Example 1 (right) as shown in Figs. 1-3 It can be seen that the metal has no damage after the nitride metal film is etched using the etching solution of Example 1; while the metal has obvious damage after the nitride metal film is etched using the etching solution of Comparative Example 1.

[0066] wherein:

[0067] The test method for performance 1, the failure time, is as follows:

[0068] The etching solution was stored at room temperature in the dark, and the external appearance after different storage times was observed, so as to investigate the stability of each.

[0069] The test method for performance 2 etching effect is as follows:

[0070] Step 1: After the etching solution for the nitride metal film is prepared in proportion, the etching solution is used to soak the nickel substrate at 40℃ for 1h.

[0071] Step 2: The substrate after soaking is rinsed with ultrapure water for three times, which is the rinsing after etching of the nitride metal film.

[0072] Step 3: After etching of the nitride metal film, whether the nitride metal film has residues and whether the metal substrate has damages are observed by an optical microscope.

[0073] The ultrapure water used in steps 1 and 2 is deionized water with a resistance of at least 18MΩ.

[0074] The test method for performance 3 etching rate is as follows:

[0075] The thickness is determined by a thickness gauge through five-point test to take an average value, and the mass of the substrate before etching is tested, and the mass of the substrate after etching is measured after etching of the nitride metal film is completed, and then the mass after etching is divided by the mass before etching, and then the thickness before etching is multiplied, and then the etching time is divided, so that the etching rate is obtained.

[0076]

[0077] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A nitride semiconductor etching solution, characterized in that, The components include the following weight proportions: 1-20 parts hydrogen peroxide; 1-10 parts sodium salt; 5-40 parts of inorganic acid; 5-10 parts organic acids; 10-30 parts ultrapure water; The sodium salt is one or more of sodium diethylenetriaminepentamethylenephosphonate, sodium pentasodium diethylenetriaminepentamethylenephosphonate, and sodium heptasodium diethylenetriaminepentamethylenephosphonate; The organic acid is one or more of formic acid, acetic acid, oxalic acid, lactic acid, and citric acid.

2. The nitride semiconductor etching solution according to claim 1, characterized in that, The concentration of the hydrogen peroxide is 1-20%.

3. The nitride semiconductor etching solution according to claim 1, characterized in that, The mass ratio of hydrogen peroxide to sodium diethylenetriamine pentamethylphosphonate is 4:1 to 1:

4.

4. The nitride semiconductor etching solution according to claim 1, characterized in that, The inorganic acid is one or more of nitric acid, hydrofluoric acid, sulfuric acid, and hydrochloric acid.

5. A method for preparing the nitride semiconductor etching solution according to any one of claims 1-4, comprising the following steps: Step 1: Weigh each component separately; Step 2: First, add ultrapure water, then add hydrogen peroxide while stirring, then add inorganic acid and sodium salt, stir until completely dissolved, and finally add organic acid, stir until uniform and transparent to obtain the nitride semiconductor etching solution.

6. Use of the nitride semiconductor etchant according to any one of claims 1-4 in the field of nitride metal film etching.

7. A method for etching a nitride metal film with the nitride semiconductor etchant according to any one of claims 1-4, characterized in that, The process includes the following steps: diluting the etching solution of the nitride metal film with ultrapure water to 50-80 times, and then immersing the substrate at 30-50°C for 1-5 hours to complete the etching of the nitride metal film.

8. The method for etching nitride metal films with the nitride semiconductor etchant according to claim 7, characterized in that, The etched substrate is rinsed two to three times in ultrapure water to complete the cleaning after etching the nitride metal film.

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