Patent ID: 7367237

Claim:
A micromachined sensor for measuring fluid shear stress, the sensor comprising: a substrate having a front-side surface, and a backside surface opposite the front-side surface; a diaphragm overlying a cavity etched within the substrate; a heat sensing element disposed on the front-side surface of the substrate and on top of the cavity and the diaphragm, the heat sensing element being electrically couplable to electrode leads formed on the backside surface of the substrate; and an electronic system connected to the backside surface and configured to measure a change in heat convection from the sensing element to surrounding fluid when the sensing element is heated by applying an electric current thereto, and further configured to derive from the change in heat convection a shear stress of the surrounding fluid that flows past the sensing element; wherein the diaphragm includes one or more access slits etched thereon, and wherein the access slits are configured to permit passage therethrough of bond wires that provide electric coupling between the sensing element on the front-side surface and the electrode leads on the backside surface.