| 摘要 |
A pressure sensor ( 30 ) for sensing a fluid pressure in harsh environments such as the air pressure in a tire, by using a first wafer substrate ( 32 ) with a front side and an opposing back side, a chamber ( 58 ) partially defined by a flexible membrane ( 50 ) formed on the front side and at least one hole ( 33 ) etched from the back side to the chamber ( 58 ); a second wafer ( 31 ) on the back side of the first wafer ( 32 ) to seal the at least one hole ( 33 ); wherein, the chamber ( 58 ) containing a fluid at a reference pressure, such that the flexible membrane ( 50 ) deflects due to pressure differentials between the reference pressure and the fluid pressure; and, associated circuitry ( 34 ) for converting the deflection of the flexible membrane ( 50 ) into an output signal indicative of the fluid pressure; wherein, the second wafer ( 31 ) is wafer bonded to the first wafer substrate ( 32 ). Wafer bonding offers an effective non-adhesive solution. It provides a hermetic seal with only minor changes to the fabrication procedure. Skilled workers in this field will readily understand that the most prevalent forms of wafer bonding are: direct wafer, or silicon fusion, bonding; anodic, or electrostatic Mallory process bonding; and, intermediate layer bonding.
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