Stress, Mechanical Properties and Composition Measurements in Sputtered Thick Alumina Films

Abstract

ABSTRACTThick r.f.-sputtered alumina is used as an overcoat material in microelectronic applications. The stress in the material is compressive and its magnitude is influenced by the sputtering conditions including the power, gas pressure and r.f. substrate bias. These parameters also affect the deposition rate, stoichiometry and sputter gas (argon) content of the material and its etch rate in hydroxide solutions. Nanoindentation measurements of the elastic modulus and hardness are presented for alumina sputtered under different bias conditions and show that the zero bias material appears to be harder and suffer than material deposited at -100V bias.