DIFFUSION BARRIERS
The integration of copper metals into the integrated circuit architectures
requires ultrathin
diffusion barriers between the silicon, SiO2 and the metal
interconnects and metal vias. Since most of these structures are inside narrow
trenches and deep vias, conformality of deposition is essential. ALD is excellent
for this application and specific metals and metal nitrides with good adhesion,
thickness control and low temperature deposition have been developed.
Examples include
WN,
TaN,
Co.