Abstract
Titanium nitride films were grown by thermal CVD from tetrakis (dimethylamido) titanium (TDMAT) and ammonia at 300 and 325 oC in a cold wall reactor at pressures of 0.5 Torr. In order to decrease the resistivity of films, multi-layer deposition TiNx films were investigated. The resistivity of deposited film was as low as to about 540 □□cm at 325 oC and 350 oC. The resistivity film deposited at 325 oC is almost 2 times lower than direct deposition. The carbon concentrations are about 10 at % in both direct and multi-layer deposition films. The oxygen concentrations are decreased significantly from 22 % to 10 % by multi-layer deposition. On the other hand, the oxygen concentration was increased with deposition. This results in a higher resistivity at high deposition temperatures. From XRD spectra and the broad diffraction ring patterns show that the films are of almost amorphous structure. Amorphous NbNx films were deposited on SiO2 by metallorganic chemical vapor deposition (MOCVD) using ethylimidotris (diethylamido) niobium(V) [EtNb=N (NEt2)3] source with NH3 at various temperatures. The diffusion barrier properties of NbNx films for Cu metallization were investigated. MOCVD NbNx thin films were obtained from the EtN=Nb (NEt2)3 MO source and NH3 at temperatures from 300 to 425 oC. The multi-layered NbNx films were formed by alternately depositing 5-nm-thick NbNx films and NH3 plasma post-treatment for 60 s with every 5nm depositing. By multi-layer deposition, both the resistivity and concentration of C and O in films were reduced significantly. The activation energy for the reaction was measured to be 0.23±0.04 eV by adding 20 sccm NH3 in the temperature range of 300 - 400 oC. 50-nm-thick NbNx film was found to effectively prevent the penetration of Cu into the substrate in samples annealed at 600 oC for 1 hr. The barrier failure mechanism in NbNx is the diffusion of Cu through the barrier layer with the formation of niobium silicide. By dipping in the silanisation solution, the hydrophobic self-organized nano molecular film (SOM) was successfully grown on the surface of the dry-etched porous methyl silsesquioxane (DE-PMSQ). The reaction was spontaneous at room temperature. The moisture adsorption on the DE-PMSQ was avoided and the surface of the SOM/DE-PMSQ was rather smooth. Leakage current and the dielectric constant measurement of DE-PMSQ and SOM/DE-PMSQ samples also showed consistent behaviors. As a result, it is promising to use the low-k PMSQ as an inter-metal dielectric (IMD) with the hydrophobic SOM grown on the DE-PMSQ.