초록 ▼

An electromechanical floating element shear-stress sensor, which may also be referred to as a flow rate sensor, having one or more transduction mechanisms coupled to a support arm of a floating element wafer such that the transduction mechanisms are normal to the force applied to a top surface of th

An electromechanical floating element shear-stress sensor, which may also be referred to as a flow rate sensor, having one or more transduction mechanisms coupled to a support arm of a floating element wafer such that the transduction mechanisms are normal to the force applied to a top surface of the floating element. The transduction mechanisms may be generally attached to a side surface of one or more arms supporting the floating element and may be coupled together and to a processor using one or more contacts extending from the backside of the floating element sensor. Thus, the floating element shear-stress sensor may have an unobstructed surface past which a fluid may flow. The floating element may also include a temperature sensing system for accounting for affects of temperature on the floating element system.

대표청구항 ▼

1. A microelectromechanical flow rate sensor, comprising:at least one floating element having a top surface residing in a plane;at least one arm extending from each corner of the floating element for supporting the at least one floating element, wherein the at least one arm includes at least one sid

1. A microelectromechanical flow rate sensor, comprising:at least one floating element having a top surface residing in a plane;at least one arm extending from each corner of the floating element for supporting the at least one floating element, wherein the at least one arm includes at least one side surface that is generally normal to an average direction of fluid flow past the top surface of the at least one floating element;at least one transduction mechanism coupled to the at least one arm and positioned generally normal to an average direction of fluid flow past the top surface of the at least one floating element.2. The microelectromechanical flow rate sensor of claim 1, wherein the at least one transduction mechanism is a piezoresistor shear-stress transduction mechanism.3. The microelectromechanical flow rate sensor of claim 1, wherein the at least one arm comprises four arms, each arm extending from a different corner of the at least one floating element, wherein two of the arms are generally parallel to each other and extend from the at least one floating element in a first direction and two other arms are generally parallel to each other and extend from the at least one floating element in a second direction generally opposite to the first direction.4. The microelectromechanical flow rate sensor of claim 3, wherein at least one transduction mechanism is coupled to each of the four arms.5. The microelectromechanical flow rate sensor of claim 4, wherein the transduction mechanisms are coupled together to form a Wheatstone bridge.6. The microelectromechanical flow rate sensor of claim 5, wherein the transduction mechanisms are coupled together using electronic through wafer interconnects in the plane in which the top surface of the at least one floating element resides and a plurality of electronic through wafer interconnects extending generally orthogonal to the top surface of the at least one floating element and toward a bottom surface of the at least one floating element, thereby providing a non-obstructed top surface.7. The microelectromechanical flow rate sensor of claim 6, wherein the electronic through wafer interconnects in the plane in which the top surface of the at least one floating element resides are formed from aluminum.8. The microelectromechanical flow rate sensor of claim 6, wherein the plurality of electronic through wafer interconnects extending generally orthogonal to the top surface of the at least one floating element and toward a bottom surface of the at least one floating element are formed from a polysilicon through wafer interconnect housed in an insulation layer.9. The microelectromechanical flow rate sensor of claim 8, wherein the insulation layer comprises silicon dioxide.10. The microelectromechanical flow rate sensor of claim 8, wherein at least one electronic through wafer interconnect is formed by back filling a through-wafer vias through the at least one floating element with an in situ-doped polycrystalline silicon.11. The microelectromechanical flow rate sensor of claim 8, wherein the through-wafer trench may be formed using deep-reactive ion etching.12. The microelectromechanical flow rate sensor of claim 1, wherein the at least one floating element is formed from silicon.13. The microelectromechanical flow rate sensor of claim 1, further comprising a layer coupled to a portion of a bottom surface of the at least one arm at an end of the at least one arm opposite to the end of the arm coupled to the at least one floating element for suspending the floating element.14. The microelectromechanical flow rate sensor of claim 13, wherein the layer is comprised of silicon dioxide.15. The microelectromechanical flow rate sensor of claim 1, further comprising at least one contact coupled to a first side of the transduction mechanism and extending generally orthogonal to the top surface of the at least one floating element and toward a bottom surface of the at least one floating element.16. The microelectromechanical flow rate sensor of claim 13, further comprising at least one coating comprising a silicon nitride hydrophobic passivation layer.17. The microelectromechanical flow rate sensor of claim 13, further comprising at least one coating on at least the top surface of the floating element.18. The microelectromechanical flow rate sensor of claim 17, wherein the coating comprises a polymer.19. The microelectromechanical flow rate sensor of claim 18, wherein the polymer comprises parylene.20. The microelectromechanical flow rate sensor of claim 1, further comprising a temperature compensation system.21. The microelectromechanical flow rate sensor of claim 20, wherein the temperature compensation system comprises a plurality of transduction mechanisms forming a Wheatstone bridge.22. A microelectromechanical flow rate sensor, comprising:at least one floating element having a top surface residing in a plane and at least four corners;at least one arm extending from each of four corners of the floating element for supporting the at least one floating element, wherein each arm extends from a different corner of the at least one floating element, wherein two of the arms are generally parallel to each other and extend from the at least one floating element in a first direction and two other arms are generally parallel to each other and extend from the at least one floating element in a second direction generally opposite to the first direction;at least one piezoresistor strain gauge transduction mechanism coupled to each of the arms and positioned generally normal to an average direction of fluid flow past the top surface of the at least one floating element.23. The microelectromechanical flow rate sensor of claim 22, wherein the transduction mechanisms are coupled together to form a Wheatstone bridge.24. The microelectromechanical flow rate sensor of claim 23, wherein the transduction mechanisms are coupled together using contacts in the plane in which the top surface of the at least one floating element resides and a plurality of electronic through wafer interconnects extending generally orthogonal to the top surface of the at least one floating element and toward a bottom surface of the at least one floating element, thereby providing a non-obstructed top surface.25. The microelectromechanical flow rate sensor of claim 24, wherein the contacts in the plane in which the top surface of the at least one floating element resides are formed from aluminum.26. The microelectromechanical flow rate sensor of claim 22, wherein the plurality of electronic through wafer interconnects extending generally orthogonal to the top surface of the at least one floating element and toward a bottom surface of the at least one floating element are formed from a polysilicon through wafer interconnect housed in a silicon dioxide insulation layer.27. The microelectromechanical flow rate sensor of claim 24, wherein at least one contact is formed by back-filling a through-wafer trench through the at least one floating element with an in-situ-doped polycrystalline silicon.28. The microelectromechanical flow rate sensor of claim 24, wherein the through-wafer trench may be formed using deep-reactive ion etching.29. The microelectromechanical flow rate sensor of claim 22, wherein the at least one floating element is formed from silicon.30. The microelectromechanical flow rate sensor of claim 22, further comprising a layer coupled to a portion of a bottom surface of the at least one arm at an end of the at least one arm opposite to the end of the arm coupled to the at least one floating element for suspending the floating element.31. The microelectromechanical flow rate sensor of claim 30, wherein the layer is comprised of silicon dioxide.32. The microelectromechanical flow rate sensor of claim 22, further comprising at least one contact coupled to a first side of the transduction mechanism and extending generally orthogonal to the top surface of the at least one floating element and toward a bottom surface of the at least one floating element.33. The microelectromechanical flow rate sensor of claim 22, further comprising at least one coating on at least the top surface of the floating element.34. The microelectromechanical flow rate sensor of claim 33, wherein the coating comprises a silicon nitride hydrophobic passivation layer.35. The microelectromechanical flow rate sensor of claim 33, wherein the coating comprises a polymer.36. The microelectromechanical flow rate sensor of claim 35, wherein the polymer comprises parylene.37. The microelectromechanical flow rate sensor of claim 22, further comprising a temperature compensation system comprising a plurality of transduction mechanisms forming a Wheatstone bridge.