Patterning method of ITO (indium tin oxide) film

Abstract

The present application discloses a patterning method of an ITO (indium tin oxide) film. A patterned mask layer is formed on the ITO film. The method includes the following steps that: an ITO film notcovered by a mask layer is removed by means of a wet etching method; and the mask layer is removed, so that a patterned ITO film is obtained. According to the wet etching method, a wet etching solution is a mixed solution composed of oxidizing acid, medium-strength acid and weak acid, and the temperature of the solution is controlled to range from 20 and 60 DEG C; the oxidizing acid and the medium-strength acid can both oxidize ITO, the weak acid is the corrosion inhibitor of the mixed solution, and therefore, the pH value of the mixed solution can be maintained, and a reaction rate can be stable and reliable; and the oxidizing acid, the medium-strength acid and the weak acid have a high etching selection ratio for the mask layer and a substrate, so that the quality of an ITO pattern canbe improved. With the wet etching method adopted, the high selection ratio of the etching solution can be achieved with safety and stability ensured, and the high-quality ITO pattern can be obtained.

Description

technical field [0001] The present application relates to the technical field of semiconductor device processing technology, in particular to a method for patterning ITO thin films. Background technique [0002] Indium tin oxide (ITO) is a transparent conductive oxide semiconductor material with stable chemical properties, excellent light transmission and good electrical conductivity. It is used as an anti-reflection layer and transparent electrode in solar cells, flat panel displays, anti-frost Architectural windows, aerospace fields have been widely used. [0003] The patterning of ITO is generally realized by photolithography plus etching, and the etching of ITO is generally divided into dry etching and wet etching. Dry etching requires etching equipment (vacuum plasma system), and the plasma in dry etching will cause ion damage to the material layer below the ITO, and most dry etching equipment is processed by a single piece of manipulator transmission. Therefore, ther...

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Problems solved by technology

Dry etching requires etching equipment (vacuum plasma system), and the plasma in dry etching will cause ion damage to the material layer below the ITO, and most dry etching equipment is processed by a single piece of manipulator transmission. Therefore, there are high requirements for the strength and rigidity of the substrate, and it cannot be etched in batches, and the etching efficiency is low

[0004] In the existing wet etching process of ITO, a single acid such as hydrochloric acid (HCl), oxalic acid (H2C2O4), or hydrofluoric acid (HF) is generally used to etch ITO. The disadvantage that the etching selectivity ratio of resist or quartz substrate is not high enough, so the ITO pattern obtained by the existing wet etching solution is not good

Adding zinc powder to hydrochloric acid can increase the selection ratio of the corrosion solution, but zinc powder is flammable and has a strong danger.

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