Method for preparing BOE (Buffer Oxide Etch) etching liquid

Abstract

The invention discloses a method for preparing a BOE (Buffer Oxide Etch) etching liquid. The method comprises the following steps: (1) sequentially adding 49wt% hydrofluoric acid (HF), 3-wt% ammonia water and super-pure water into a reactor, and stirring to react for 6-12 hours at the room temperature, so as to obtain a mixture of hydrofluoric acid (HF) and ammonium fluoride (NH4F); and (2) sequentially adding additives and alkyl ammonium sulfate anionic surfactants into the obtained mixture, stirring and mixing for 6-18 hours at the room temperature so as to obtain the transparent BOE etching liquid after uniform mixing. The BOE etching liquid prepared by using the method is high in etching selectivity, and the contact angle of the BOE etching liquid to a silicon wafer is remarkably reduced. In addition, the preparation method is simple to operate, and the etching liquid is low in impurity content.

Description

technical field [0001] The invention relates to a preparation method of a wet etching solution composition, more particularly to a preparation method of a BOE etching solution. Background technique [0002] Buffered oxide etchant (BOE) achieves the purpose of etching by removing the oxide layer of the semiconductor silicon wafer film that is not covered by photoresist. It is widely used in the manufacture of microstructures and silicon-based light-emitting devices. The preparation method of BOE etching solution is generally: using ultrapure water as a solvent, mixing a certain concentration of hydrofluoric acid and ammonium fluoride in a certain proportion to obtain the required ratio of BOE etching solution. However, the surface tension of the BOE etching solution obtained by the above preparation method is very high, and the wettability to the semiconductor silicon wafer etching layer is very poor, resulting in severe deformation of the etching pattern. [0003] In order ...

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Problems solved by technology

However, the BOE etching solution containing the above-mentioned surfactants cannot quickly infiltrate the semiconductor silicon wafer. The contact angle of the BOE etching solution on the semiconductor silicon wafer is relatively high, and the spreading speed of the BOE etching solution on the surface of the semiconductor silicon wafer is relatively slow, and its penetration is complicated. Poor ability to micro surface

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