Electric field and temperature-induced removal of moisture in nanoporous organosilicate films

The effects of bias-temperature-stress (BTS) or simply temperature-stress (TS) on nanoporous low-k methylsilsesquioxane films are studied. Initially, the as-given and O-2 ashed/etched films exhibit physical adsorption of moisture as revealed from the electrical behavior of the samples after 15 days. The temperature stressing at 170degreesC volatilized the adsorbed water but is unable to remove chemisorb and hydrophillic Si-OH groups. As a result, the TS films remain susceptible to moisture. BTS at 170degreesC also removes adsorbed water. More important, the surfaces under the metal-insulator structure were dehydroxylated by breaking the chemisorb Si-OH group facilitating the formation of siloxane bonds that prevents adsorption of moisture even after 60 days. (C) 2004 American Institute of Physics.