Fluorinated amorphous carbon films (a-C:F) deposited by plasma enhanced chemical vapor deposition with low dielectric constant (K∼2.3), thermal stability (higher than 400 °C) and acceptable adhesion to a cap layer such as SiOF or SiO2 were obtained by varying the range of content ratios between carbon and fluorine, the rf power, the process pressure and the base temperature. Standard x-ray photoelectron spectroscopy and thermal desorption spectroscopy metrologies were employed to characterize the deposited a-C:F films. The damascene pattern with 0.15 μm and an etching selectivity of more than 50 (a-C:F/SiOF, SiO2) was implemented by a mixture of etching gases of N2+O2. The bias power, rf power and gas flows were incorporated to optimize the etching recipe for achieving a damascene profile with a high aspect ratio. The scanning electron microscope results showed that a better etch profile can be obtained at higher bias power. In our damascene architecture, the etching stop layer or hard mask of both SiOF and SiO2 was studied. The SiOF, providing a lower dielectric constant than SiO2, would especially reduce the entire effective dielectric constant. Furthermore, we integrated electroplated copper into trenches or vias as small as 0.15 μm, with aspect ratio of 6.

A novel, multilayered Ti/TiN diffusion barrier is proposed and successfully applied for Al metallization. The multilayered Ti/TiN structure is effective in enhancing the barrier properties since the very thin Ti layer inserted into titanium nitride (TiN) barrier can cause disruption of the TiN columnar growth and reduction of open grain boundaries resulting in retarded interdiffusion between metal and silicon. Multilayered Ti/TiN films are deposited sequentially by sputtering without breaking vacuum. It is found that TiN grain boundaries are discontinuous when a Ti layer is inserted into TiN. Multilayered Ti/TiN has a better barrier performance than single-layer TiN in Al metallization. However, the barrier performance is related to the number and thickness of the inserted Ti layers, because increasing titanium will enhance chemical reactions between Al and barrier layers, and produce more titaniumaluminum compounds. The total thickness of introduced Ti layers should be reduced to improve barrier performance.

In situ real-time monitoring of profile evolution during plasma etching of mesoporous low-dielectric-constant SiO 2Effect of sputtering with hydrogen dilution on fluorine concentration of low hydrogen content fluorinated amorphous carbon thin films with low dielectric constant

The electrical characteristics of Ta/Ta 2 O 5 /Ta capacitors are improved by treatments with inductively coupled N 2 O plasma. A low-temperature ͑250°C͒ and short ͑5 min͒ process was used to reduce the leakage current and improve the reliability. A low leakage current density ͑4.0 ϫ 10 −10 A/cm 2 under 1 MV/cm͒, high breakdown field ͑4.2 MV/cm at 10 −6 A/cm 2 ͒, and lifetime of over 10 years at 1.61 MV/cm is obtained for the Ta/Ta 2 O 5 /Ta capacitor with the inductively coupled N 2 O plasma treatment. The conduction mechanism of the leakage current in the Ta/Ta 2 O 5 /Ta capacitor is discussed using current-voltage analyses and shows that the leakage current of the Ta/Ta 2 O 5 /Ta capacitor is dominated by Schottky emission. N 2 O plasma treatment can effectively reduce oxygen vacancies and the surface roughness of the Ta 2 O 5 film, inhibiting the conduction of the leakage current.