Surface degradation of Sn-contained electronic packaging materials in simulated body fluids

For electronic medical devices which are intended to function inside the human body is very important to keep unchangeable their structural and functional properties under an influence of aggressive physiological factors. For stability testing of some electronic materials in laboratory conditions a simulation of human body fluid environment has been used. Sn-contained electronic packaging materials as a) FR4 + 1.2 44 m chemical Sn; b) FR4 + hot air leveling (HAL) Sn and c) FR4 + Sn 3.5 Ag 0.7 Cu were brought in dynamical interaction with artificial blood plasma, cerebrospinal fluid and 0.9% NaCl solution. Alterations in the surface topography and its chemical composition were studied. Materials mass losses in the surface ratio were determined depending on the soaking time. As a protection procedure against the influence of aggressive fluidic environment 1 mum and 2.5 mum layers of parylene C were deposited on chemical Sn and HAL Sn surfaces. Hydrolytic stability of protected materials has been determined.