CrSb2Te thin film as a dry resist and its etching mechanism for lithography application

Highlights: • CrSb₂Te thin film is used as a dry resist. • CrSb₂Te thin film possesses etching selectivity in CHF₃/O₂ mixed gases. • Sb crystals and CrSb₂Te₃ phase are formed in CrSb₂Te thin film after exposure. • Sb crystals of the laser-irradiation film can be readily broken in etching process. • The as-deposited film possesses higher etching resistance owing to the Cr addition. Lithography has important applications in chip manufacturing, micro-electro-mechanical system, nanostructure fabrication et al. Photoresist is a key factor for the lithography. However, current organic resists suffer from poor line-edge roughness, environmentally unfriendly et al. In parallel, conventional wet development can readily cause the undercut of photoresist due to its isotropic etching. In this work, CrSb₂Te thin film, as an inorganic resist, was prepared and its etching characteristics were investigated via dry development with CHF₃/O₂ mixed gases. It is found that superior etching selectivity can be realized in the CrSb₂Te thin film. In order to elucidate the lithography characteristics, XRD, EDS, XPS, and Raman spectra are obtained. The results indicate that laser irradiation leads to the generation of Sb crystals and CrSb₂Te₃ phase. According to dry etching, Sb crystals of the laser-irradiation film can be readily broken. On the other hand, the as-deposited thin film possesses higher etching resistance owing to the uniform distribution of Cr in Sb₂Te along with the formation of Cr-Sb and Cr-Te bonds. Therefore, CrSb₂Te thin film may be utilized as a superior inorganic resist for the field of lithography.