Hexamethyldisilazane vapor treatment of plasma damaged nanoporous methylsilsesquioxane films: Structural and electrical characteristics

Repair of plasma damaged nanoporous organosilicate films carried out by hexamethyldisilazane (HMDS) vapor treatment was investigated as a function of temperature. Capacitance–voltage measurements were carried out before and after HMDS vapor treatment. The dielectric constant measurements confirm that the HMDS vapor treatment facilitates only partial curing of the plasma damaged films, as also observed from the Fourier transform infrared absorption measurements. Bias temperature stress measurements for samples with copper (Cu) metal electrodes reveal a shift of − 35 V in the capacitance–voltage curve for samples cured at 55 °C whereas negligible shift is observed for samples treated above 80 °C. This behavior suggests the existence of a dense solid layer on the top surface of the samples treated above 80 °C, hindering the diffusion or movement of Cu ions into the dielectric. Direct imaging of the HMDS vapor treated plasma damaged films using scanning electron microscope clearly shows the existence of two distinct layers, with the top layer (at the film–air interface) being denser than the bottom layer at the film–substrate interface.