Development of micro-system encapsulation for silicon devices which are in contact with human cells

In this paper the CEA LETI proposes a silicon test vehicle and method to quantify the degradation of packaging in a biological medium. Those developments are suited for medicals devices which are potentially in contact with human cells. Different solutions of encapsulation, performed at the wafer level in clean room, are presented and compared. Test vehicles were made on silicon wafer including AlSi, Cu or WN patterns which are common used in microelectronics but known to be nonbiocompatible. The barrier properties of thin layer such as SiO
₂
, Al
₂
O
₃
, TiO
₂
, Pt and TiTiN were evaluated in PBS (Phosphate Buffer Saline) solution. Corrosion was observed thanks to optical microscope and SEM. It was shown in this study that a multilayer of SiO
₂
/Al
₂
O
₃
/TiO
₂
and Pt has successfully preserved AlSi lines from degradation during 90 days in PBS at 90°C.