Metal contact systems for semiconductor-based pressure sensors exposed to harsh chemical and thermal environments

摘要

Highly corrosion resistant electrically conductive contact systems suitable for semiconductor pressure sensor devices exposed to acidic, elevated temperature environments, such as automotive exhaust gas environments, are disclosed. The preferred embodiment (10) comprises a platinum top layer (26), and a tantalum lower layer (24). Both are highly electrically conductive layers and exhibit corrosion resistance to acidic environments. The top layer of the metallization also provides a suitable material for the external connectivity (e.g., wire bonding, solder bumping, chip-chip fusion). The lower layer of the metallization also serves as an adhesion layer between the top metal and lower layers, typically silicon based glasses and in some cases serves as a diffusion barrier.