Corrosion Behavior of Parylene-Metal-Parylene Thin Films in Saline

In this paper, we study the corrosion behavior of parylene-metal-parylene thin films using accelerated-lifetime soak tests. The samples under test are thin film resistors with a 200 nm layer of Au sandwiched by parylene-C on both sides, fabricated with parylene-metal skin technology. The samples are tested in hot saline both passively and actively, and different failure modes are observed using optical and electron-beam metrologies. Bubbles and delamination are first seen in the samples after 2 days of soaking under passive conditions, and followed by metal corrosion. While under active conditions, either bubbles or parylene breakdowns are observed depending on the thickness of parylene packaging. These results contribute to a better understanding of the failure mechanisms of parylene packaging in body fluids