Etching liquid for silicon system multilayer films

Abstract

The invention discloses an etching liquid for silicon system multilayer films. The etching liquid comprises a hydrofluoric acid solution, an ammonium fluoride solution, a surfactant and a compound represented by a general formula shown in the description; and in the formula, R1 is one of an amino group, hydrogen, oxygen and a hydroxyl group, and R2 is one of fluorine, chlorine, hydrogen, a hydroxyl group and a C1-C4 alkyl group. The etching liquid for silicon system multilayer films allows the etching speed of a silicon nitride layer to basically same to the etching speed of a silicon oxide layer, and has a good etching effect.

Description

technical field [0001] The invention relates to the technical field of etching an insulating layer of a polysilicon thin film transistor, and more specifically relates to an etchant for a silicon-based multilayer thin film. Background technique [0002] At present, the low-temperature polysilicon thin-film transistor (LTPS TFT-LCD) of liquid crystal display has been developed and is increasingly mass-produced. The layer is a silicon oxide film. For the processing technology of this structure, using hydrofluoric acid or BOE (buffered oxide etchant, the main components are hydrofluoric acid, ammonium fluoride and water) wet etching is an important step in the preparation of high-performance thin film transistors. [0003] The low-temperature polysilicon thin film transistor insulating layer etching process is divided into two steps. The first step is to remove the ILD layer and part of the GI silicon oxide layer by dry etching, and the remaining GI silicon oxide layer is remo...

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Problems solved by technology

But in order to make the etching rate of silicon nitride layer and silicon oxide layer substantially consistent, the addition of above-mentioned ethylene glycol or propylene glycol must be more than 30% (w / w), and the etching rate of silicon nitride layer and silicon oxide layer is only It is difficult to meet the processing requirements of thin film transistors

Moreover, the addition of surfactants can only improve the surface tension of the etching solution and improve the uniformity of etching, but cannot make the etching speed of the silicon nitride layer and the silicon oxide layer basically the same.

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