Fundamental relationship between capacitance-time measurements and gravimetric measurements for water absorption in a low-k dielectric

Capacitance-time measurements have been used to determine the transient water absorption of a Benzocyclobute (BCB) film. To derive the absolute amount of water from the capacitance change the Debye equation was applied with the assumption, that the absorbed water can be considered as single molecules without any interactions to each other and to the low-k dielectric. The results have been verified by using a microbalance system which allows a direct determination of the amount of water in the dielectric layer.