Mechanical properties of low-and high-k dielectric thin films: A surface Brillouin light scattering study

摘要

Surface Brillouin light scattering measurements are used to determine the elastic constants of nano-porous low-k SiOC:H (165 nm) and high-k HfO_2 (25 nm) as well as BN:H (100 nm) films grown on Si substrates. In addition, the study investigates the mechanical properties of ultra-thin (25 nm) blanket TiN cap layers often used as hard masks for patterning, and their effects on the underlying low-k dielectrics that support a high level of interconnected porosity. Depending on the relative material properties of individual component layers, the acoustic modes manifest as confined, propagating, or damped resonances in the light scattering spectra, thereby enabling the mechanical properties of the ultra-thin films to be determined.