抄録
An absolute pressure sensor has reference cavity and elecrtical feedthrough from the cavity. The reference cavity has to be hermetically sealed, but the electrical feedthrough at the bonding surface makes small leakage.
In this paper, a new feedthrough structure is proposed and is applied to a piezoresistive pressure sensor.
A pyrex glass and a sillicon are used for this structure. The pyrex glass has fine through-holes engraved by electrolytic discharge drilling. The silicon has the diffused electrical feedthrough from the reference cavity. The reference cavity is hermetically sealed by glass-silicon anodic bonding. Bonding pads are made by Cr-Cu-Au mask evaporation to the glass holes. Lead wires are connected to the pads inside the glass hole with conductive epoxy or solder.
The advantages of this structure are as follows.
(1) Reference cavity is hermetically sealed without leakage by glass-silicon anodic bonding.
(2) Sensor is assembled in small size.
(3) Lead wires are attached at the opposite side of the diaphragm and strongly enough.
The piezoresistive absolute pressore sensor with this structure is small and high performance. This structure is also useful for capacitive absolute pressure sensors.
