Qualification of the Barrier Properties of ALD-coated Polymer Films with Humidity Sensors

For the encapsulation of microelectronics or active implants, hermetically sealed, thin, and flexible materials are desirable. Research is focused on the deposition of ultra-thin metal oxide layers, which are deposited onto the substrates using the atomic layer deposition (ALD) process. The evaluation of such layers can be performed by the so-called water vapor transmission rate (WVTR). We present an inexpensive method for the determination of the effective WVTR by humidity sensors and a suitable experimental setup, in which we have measured three different layer systems with four different total thicknesses, which were applied on polymer films, for validation.