The mechanical properties of two viscoelastic thin films were measured, a polyimide and a low-k polymer dielectric. The static modulus and hardness were obtained from nanoindentation experiments using an elastic-plastic unloading model (J. Mater. Res., 13, 421 (1998)). Nanoindentation creep tests were also performed, where a value for the modulus was extracted by fitting the data to an equation based on the three-element standard linear solid model. Aside from being comparable to values reported in the literature, the moduli from creep experiments are at most 1.3 times lower than the static moduli. This decrement can be attributed to the differences in strain rate for the two methods and the effect of adhesive forces.
|Original language||English (US)|
|Number of pages||6|
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - Jan 1 2002|