Effect of accelerated hydrothermal aging on the durability of Si-based dielectric thin films

Extensive reliability testing is performed on microelectronic products nowadays to ensure full life cycle opera-tion. Accelerated hydrothermal aging is used to evaluate product sensitivity to the absorption of water and detect any related reliability issue. Sensitivity to accelerated hydrothermal aging (85 C and 85% relative humidity for 1000 h) is studied for two dielectric materials that are used in microelectronic product manufacturing, the undoped silicate glass (SiO2:H) and the porous ultra-low k oxide (SiOC:H). Mass, residual stress, mechanical properties and FTIR analyses show that both materials are sensitive to water absorption. SiO2:H shows water absorption through new silanol bonds formation disorganizing the main Si network and thus, modifying the mechanical properties. On the contrary, SiOC:H absorbs water into its porous structure with little or no bonding to the main Si network, which does not induce any significant change in the mechanical properties.