Micro-electromechanical structure with low sensitivity to thermo-mechanical stress

A method of compensating thermo-mechanical stress accumulated in a microelectromechanical structure, comprising the steps of:

• determining a level of the thermo-mechanical stress that is accumulated in the structure, the thermo-mechanical stress causing a displacement to a proof mass that responds to acceleration by displacing and tilting with respect to a moveable mass rotational axis;
• determining an offset value and a sensitivity drift associated with an output according to the level of the thermo-mechanical stress, the output being generated by the structure in response to the acceleration;
• and
• adjusting geometry and configuration of a plurality of elastic elements to compensate the offset and the sensitivity drift, the plurality of elastic elements, connected to at least one anchor and the proof mass, being applied to support the proof mass, wherein at least one of the plurality of elastic elements is a T-shaped element having its leg to couple at the proof mass, and its arms to anchor at the at least one anchor, and wherein the arms of the T-shaped element are located on the two opposite sides of the moveable mass rotational axis and have widths and lengths that are designed to reduce a displacement caused by thermo-mechanical stress on the two opposite sides.

An out-of-plane accelerometer, comprising:

• a substrate;
• a proof mass, suspended above the substrate, the proof mass responding to acceleration along a z-axis by displacing and tilting with respect to a moveable mass rotational axis that is located in the plane of the proof mass;
• at least one anchor, fixed on the substrate, the at least one anchor being coupled to support the proof mass;
• and
• a plurality of elastic elements, connected to the at least one anchor and the proof mass, geometry and configuration of the plurality of elastic elements being adjusted to reduce a displacement caused by thermo-mechanical stress on two sides of the moveable mass rotational axis, wherein a first subset and a second subset of the plurality of elastic elements are arranged to support the proof mass from two opposite sides of the proof mass, respectively, and the first and second subsets of elastic elements mirror each other in their geometry and configuration with respect to a central line that is perpendicular to the moveable mass rotational axis and passes a center of the proof mass.