Fabrication Of Chip Scale Piezoresistive Pressure Sensors Using Screen-Printed Glass Frit Packaging

This paper presents the chip scale packaging of pressure sensors using glass frit technology. The silicon wafer of pressure sensors is sandwiched between the anodically bonded bottom glass wafer with an etched hole, and the glass-frit bonded top glass wafer with the solder bumps. The screen-printed glass frit technique can overcome the planarization problem associated with metallization of the piezoresistors on the silicon wafers. The diffused piezoresistive Wheastone bridge is fabricated on the diaphragm enabling to measure the pressure range between 0 to 0.4 bars. At the same time the tensometric piezoresistive bridge is integrated to monitor the residual stress induced by this packaging technique.