Abstract:

We address moisture diffusion in epoxy molding compounds (EMCs) at temperatures higher than 100 °C. The objectives of this paper are thus: 1) to obtain diffusion properties of EMCs in both absorption and desorption modes at a wide range of temperatures; 2) to establish a non-Fickian correlation for diffusivity; and 3) to assess moisture diffusion behaviours during a solder re-flow process, described by two different Fickian diffusivities of absorption and desorption and the non- Fickian diffusivity. An experimental procedure is established to measure the diffusivity and solubility of selected EMC materials. The results are utilized in a numerical simulation to analyse the effect of the non-Fickian diffusion characteristics on the moisture distribution during the re-flow process.

Index Terms: Diffusion property, moisture diffusion, re-flow process.

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