Stability and common mode sensitivity of piezoresistive silicon pressure sensors made by different mounting methods

Mechanical stress introduced in a silicon diaphragm chip from the support chip or the substrate affects the performance of silicon pressure sensors. The influence of this effect on long-term stability, thermal zero shift, and common mode pressure sensitivity has been evaluated on differential piezoresistive sensors. The following different structures have been tested and compared: (1) unmounted diaphragm chips as reference; (2) silicon support chips sealed to diaphragm chips by silicon-to-silicon anodic bonding; (3) silicon support chips sealed to diaphragm chips with screen printed solder glass; and (4) Pyrex 7740 borosilicate glass substrates sealed to diaphragm chips by anodic bonding. The results from these tests show that all these methods can be used for high-performance piezoresistive pressure sensors. Silicon-to-silicon anodic bonding is shown to be the best method with respect to thermal zero stability and common mode pressure stability.<>