Development of micropackage technology for biomedical implantable microdevices using parylene C as water vapor barrier coatings

This paper presents a study on micro package technology using conformal coating of parylene C as non hermetic packaging material for implantable biomedical devices. Different thicknesses (2-25 μm) of parylene C were coated on patterned two electrode PCB test board for electrical performance measurement. Experiments were carried out in 85°C salient solutions for accelerated testing. Test results on survive life will be presented, which serves as a baseline for minimum coating thickness of implantable biomedical devices. Water vapor transmissions (WVT) through parylene C thin films combined with additional oxide/nitride coatings to form multilayer vapor barrier films were also evaluated. Test results show that multilayered coating approach has improved the WVT rate by a factor of 54.7%, compared with a single parylene C coating during 24 hours test period.