Study of the effect of Sn grain boundaries on IMC morphology in solid state inter-diffusion soldering.

This paper reports on 3D phase field simulations of IMC growth in Co/Sn and Cu/Sn solder systems. In agreement with experimental micrographs, we obtain uniform growth of the CoSn phase in Co/Sn solder joints and a non-uniform wavy morphology for the CuSn phase in Cu/Sn solder joints. Furthermore, simulations were performed to obtain an insight in the impact of Sn grain size, grain boundary versus bulk diffusion, IMC/Sn interface mobility and Sn grain boundary mobility on IMC morphology and growth kinetics.

Active electrode arrays by chip embedding in a flexible silicone carrier.

Future cochlear implants demand a higher density of stimulation sites (electrodes) and enhanced functionality (e.g. feedback information).