Temperature coefficient of offset compensation for force sensor and strain gauge
AssigneeNextInput, Inc.
InventorsJulius Minglin Tsai, Dan Benjamin
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Abstract
MEMS force sensors for providing temperature coefficient of offset (TCO) compensation are described herein. An example MEMS force sensor can include a TCO compensation layer to minimize the TCO of the force sensor. The bottom side of the force sensor can be electrically and mechanically mounted on a package substrate while the TCO compensation layer is disposed on the top side of the sensor. It is shown the TCO can be reduced to zero with the appropriate combination of Young's modulus, thickness, and/or thermal coefficient of expansion (TCE) of the TCO compensation layer.
Claims20
A microelectromechanical (“MEMS”) force sensor for providing temperature coefficient of offset (TCO) compensation, comprising:
- a sensor substrate configured to receive an applied force, wherein the sensor substrate comprises a top surface and a bottom surface opposite thereto;
- a package substrate;
- a solder bump that connects the sensor substrate to the package substrate;
- a sensing element arranged on the bottom surface of the sensor substrate, wherein the sensing element is configured to convert a strain on the bottom surface of the sensor substrate to an electrical signal that is proportional to the strain, wherein:
- the sensing element comprises a piezoelectric element;
- and
- the piezoelectric element is sandwiched between the solder bump and the sensor substrate;
- and
- a compensation layer arranged on the top surface of the sensor substrate, wherein the compensation layer has a thermal coefficient of expansion that is different than a thermal coefficient of expansion of the sensor substrate.
Dependencies are inferred from the claim text.