Importance

Loading Importance Indicators...

Abstract

A pressure sensor (30) for sensing a fluid pressure in harsh environments such as the air pressure in a tire. The sensor has a dual wafer construction with a first wafer substrate (32) that has a cavity extending from its front side to the opposing back side. A flexible membrane (50) seals the cavity at the front side and a second wafer (31) seals the cavity at the back side of the first wafer (32) to form a chamber (58) containing a fluid at a reference pressure. The flexible membrane (50) deflects due to pressure differentials between the reference pressure and the fluid pressure and associated circuitry (34) for converts the deflection of the flexible membrane (50) into an output signal indicative of the fluid pressure. The second wafer (31) is wafer bonded to the first wafer substrate (32) as 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.

Loading the Abstract Image...

First Claim