Thermally Annealed Molecular Layer-Deposited Indicone: Structural Analysis and Area Selective Deposition Application

Semiconductor devices have become smaller, more complicated, and structuralized in three dimensions. Area selective deposition is one of the promising bottom-up process techniques for self-alignment or improved overlay to achieve errorless alignment. The surface chemistry is crucial to adjust precursor adsorption. In this research, graphitic carbon fabricated by molecular layer deposition is utilized for inhibiting precursor adsorption. An indicone film, which has an indium-based metalcone structure, is fabricated using bis(trimethysily)-amidodiethylindium and hydroquinone. The structure of the indicone film is reconstructed to graphitic carbon with a small oxygen content on the surface by a thermal annealing process. The atomic structures of as-dep and thermally-annealed indicone films are analyzed. The organic structure is transformed to graphitic carbon above an annealing temperature of 450 °C, where indium is completely removed with annealing temperatures above 600 °C. The thermally-annealed indicone is used for deactivating film growth, which can delay 60 cycles of ZnO growth (equivalent to a thickness of ≈11 nm). In addition, to energetically demonstrate precursor adsorption on graphitic carbon, the density functional theory is utilized. Finally, ZnO as a blocking layer is selectively deposited on a grated line pattern to interconnect the SiO₂ line pattern by transferring a hard mask.