Titanium-tungsten alloy etching solution and preparation method thereof

Abstract

The invention relates to a titanium-tungsten alloy etching solution and a preparation method thereof. The etching solution is prepared from 10-16% of H2O2, 5-10% of phosphoric acid, 0.1-1% of organic acid, 2-4% of alkali, 1-5% of inhibitor and the balance of deionized water. Wherein the inhibitor can inhibit corrosion of the etching liquid to the Ti film layer and protect the Ti film layer from being corroded or slightly corroded. The preparation method comprises the step of sequentially adding the deionized water, the phosphoric acid, the organic acid, the alkali, the inhibitor and the H2O2 into a mixing kettle. According to the method, the TiW layer can be etched slowly and uniformly, the morphology after etching is accurately controlled, and meanwhile, the Ti layer can be effectively protected from being corroded or slightly corroded.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor material processing, and in particular relates to a titanium-tungsten alloy etching solution and a preparation method thereof. Background Art

[0002] Tungsten-based metals are widely used in semiconductor manufacturing, such as gates, lines, barrier layers and through holes of thin film transistors. However, the commonly used titanium-tungsten alloy etching solutions are generally strong acid etching solutions containing hydrofluoric acid or other inorganic acids, mixtures of hydrogen peroxide and inorganic acids and organic acids, or mixtures of hydrogen peroxide and alkaline substances such as potassium hydroxide. These etching solutions will cause significant damage to the Ti layer when used.

[0003] Patent No. CN104911595B discloses a TiW etching solution, whose main components are hydrogen peroxide, ammonia water, and phosphoric acid. This system is highly corrosive to the Ti layer; Patent No. CN112981405B discloses a TiW etching solution, whose main components are hydrogen peroxide, organic acid and additives, but does not describe the corrosion of the Ti layer; Patent No. CN108130535B discloses a TiW etching solution, whose main components are oxidants, pH regulators, pH buffers, copper corrosion inhibitors, etc. This invention can introduce pH buffers into the etching solution, and the Cu layer will not be corroded due to the decrease in pH.

[0004] Since the titanium-tungsten etching solution currently used in the market is highly corrosive, has poor protection for the Ti layer, and has low stability, it is a technical problem to provide a solution with good corrosion effect, low corrosion to the Ti layer, and long service life. Summary of the invention In order to solve the above problems, the present invention aims to provide a titanium-tungsten alloy etching solution and a preparation method thereof, which can etch the TiW layer slowly and evenly, accurately control the morphology after etching, and at the same time do not corrode or slightly corrode the Ti layer metal. The technical solution of the present invention is as follows: A titanium-tungsten alloy etching solution, comprising the following components by mass fraction: 10-16% H2O2, 5-10% phosphoric acid, 0.1-1% organic acid, 2-4% alkali, 1-5% inhibitor, and the balance is deionized water.

[0005] Preferably, the etching solution further comprises the following components by mass fraction: 0.1-1% organic acid.

[0006] Preferably, the organic acid is a combination of at least one or more of acetic acid and citric acid.

[0007] Preferably, the base is a combination of at least one or more of ammonia water, potassium hydroxide, sodium hydroxide and tetramethylammonium hydroxide.

[0008] Preferably, the inhibitor is a sulfonic acid compound, including at least one or more of methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, p-hydroxybenzenesulfonic acid, o-cresolsulfonic acid, and p-styrenesulfonic acid.

[0009] Preferably, the pH value of the titanium-tungsten alloy etching solution is in the range of 3.0 to 7.0. The preparation method of the titanium-tungsten alloy etching solution comprises adding deionized water, phosphoric acid, organic acid, alkali, inhibitor and H2O2 in a mixing kettle in sequence.

[0010] Beneficial effects of the present invention: The invention provides a titanium-tungsten alloy etching solution, which can etch a TiW layer slowly and evenly, accurately control the morphology after etching, and can effectively protect the Ti layer from being corroded or slightly corroded. DETAILED DESCRIPTION

[0011] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0012] In the context of this specification, except for the contents explicitly described, any matters or items not mentioned directly use the technology known in the art. Moreover, any embodiment described in this patent can be freely combined with one or more other embodiments described in this patent, and the technical solutions or technical ideas formed thereby are regarded as part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed in this patent, unless a person skilled in the art considers that the combination is obviously unreasonable.

[0013] The data points disclosed in the present invention include not only the specifically disclosed numerical points, but also the endpoints of each numerical range. Any combination of these data points should be regarded as the disclosed or recorded range of the present invention, regardless of whether these numerical points are disclosed one by one in this article. The etching solution of the present invention is prepared by simply and evenly mixing the components described in Table 1, and then mixing with H2O2 having a concentration of 31% in a volume ratio of 1:1 before use. Components and contents of Examples 1-16 of the present invention and Comparative Examples 1-6.

[0014] Table 1 shows the components and contents of the etching solutions of Examples 1 to 16 and Comparative Examples 1 to 6

[0015] Cut the test piece into 1.5*1.5 cm 2 The size of the test piece was then immersed in a 30℃ solution for 20 minutes, washed with deionized water and dried with N2, and then the etching effect was photographed with a SEM, and the etching rates of the TiW and Ti layers were calculated respectively.

[0016] The results of the examples and comparative examples are summarized in Table 2. Table 2 shows the etching rates and selectivities of different film layers in Examples 1 to 16 and Comparative Examples 1 to 6.

[0017] It can be seen from the above experimental results that the etching solution of the acidic hydrogen peroxide system can etch Ti and W metals at the same time, and the etching solution provided by the present invention can corrode the TiW layer more slowly. Under the synergistic effect of the organic acid and the inhibitor, the etching solution can not corrode or slightly corrode the Ti layer.

[0018] The technical solution of the present invention is explained through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above specific embodiments to be implemented. Any improvements made by technicians in the relevant field based on the present invention, or equivalent replacement of the materials selected by the present invention, etc., fall within the scope of protection of the patent.

Claims

1. A titanium-tungsten alloy etching solution, characterized in that: The etching solution comprises the following components by mass fraction: 10~16% H2O2, 5~10% phosphoric acid, 0.1~1% organic acid, 2~4% alkali, 1~5% inhibitor, and the balance is deionized water.

2. The titanium-tungsten alloy etching solution according to claim 1, characterized in that: The etching solution also includes the following components by mass fraction: 0.1-1% organic acid.

3. The quartz crystal etching solution according to claim 2, characterized in that: The organic acid is at least one or more of acetic acid and citric acid.

4. The titanium-tungsten alloy etching solution according to claim 1, characterized in that: The alkali is a combination of at least one or more of ammonia water, potassium hydroxide, sodium hydroxide and tetramethylammonium hydroxide.

5. The titanium-tungsten alloy etching solution according to claim 1, characterized in that: The inhibitor is a sulfonic acid compound, including at least one or more of methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, p-hydroxybenzenesulfonic acid, o-cresolsulfonic acid, and p-styrenesulfonic acid.

6. The titanium-tungsten alloy etching solution according to claim 1, characterized in that: The pH value of the titanium-tungsten alloy etching solution ranges from 3.0 to 7.

0.

7. The method for preparing the titanium-tungsten alloy etching solution according to any one of claims 1 to 6, characterized in that: Deionized water, phosphoric acid, organic acid, alkali, inhibitor and H2O2 were added to the mixing kettle in sequence.

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