Selective wet etching of metal nitrides

Abstract

In one embodiment, the present invention relates to a wet etching composition including hydrogen peroxide; an organic onium hydroxide; and an acid. In another embodiment, the invention relates to a method of wet etching metal nitride selectively to surrounding structures comprising one or more of silicon, silicon oxides, glass, PSG, BPSG, BSG, silicon oxynitride, silicon nitride and silicon oxycarbide and combinations and mixtures thereof and / or photoresist materials, including steps of providing a wet etching composition including hydrogen peroxide, an organic onium hydroxide, and an organic acid; and exposing a metal nitride to be etched with the wet etching composition for a time and at a temperature effective to etch the metal nitride selectively to the surrounding structures.

Description

technical field [0001] The present invention relates to the wet etching of metal nitrides, such as titanium, tungsten, tantalum, hafnium and zirconium nitrides and mixtures thereof, for materials such as glass, BPSG, BSG, silicon dioxide, silicon nitride and photoresist The surrounding structure formed by the agent is selective. Background technique [0002] Lithography generally consists of the following steps. First, a photoresist (PR) material is coated onto the surface of the wafer by a suitable method such as spin coating. Then, the PR layer is selectively exposed to radiation such as ultraviolet light, electrons, or X-rays, wherein the exposed area is defined by an exposure tool, a mask, or computer data. After exposure, the PR layer is developed, which destroys the unwanted parts of the PR layer. area, thereby exposing the corresponding area of ​​the underlying layer. Depending on the resist type, the developing stage may destroy exposed or unexposed areas. Then, ...

AI Technical Summary

Problems solved by technology

[0007] A longstanding problem with the use of these standard, conventional wet etchants is their lack of selectivity

These wet etchants often attack surrounding structures, resulting in etching, or especially in the case of some photoresists, increased and / or loss of adhesion of the photoresist-coated substrate

As critical dimensions continue to be reduced, this lack of selectivity becomes less and less acceptable

Images