Here is the abstract you requested from the IMAPS_2012 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|A simple calculation procedure for water vapour permeation into polymer packages containing electronics|
|Keywords: Electronics packaging, Humidity measurement, Implantable biomedical devices|
|When packaging electronics to protect from the effects of water vapour, it is essential to be able to predict how moisture will permeate the enclosure. In the context of short term medical implantation of electronic devices for instance, packages made of a ‘permeable' material such as a polymer may be acceptable, provided calculations and tests show that low internal relative humidity is guaranteed within the device's lifetime. Fick's laws applied to water diffusion have a solution which can either be solved numerically, or approximated accurately with the single exponential ‘QSS model'. This paper adapts the so-called QSS model to the case of moisture ingress into a package which has walls or elements of different thicknesses or properties. Using an electrical analogy, we propose a model which allows estimating the change in relative humidity with time inside the enclosure cavity, using a simple calculation method. Tests are also led to evaluate the validity of this model experimentally.|
University College London