MEMS Accelerometer Elastic Coupling for Thermo-Mechanical Stress Compensation
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Solution Overview
Problem
Thermo-mechanical stress in microelectromechanical structures (MEMS) devices, such as accelerometers, leads to offset and sensitivity drift in sensing outputs due to non-uniform stress accumulation during manufacturing, packaging, and aging, compromising device performance.
Innovation Solution
Incorporating elastic elements into the coupling structures that connect stationary electrodes to anchors on a substrate, allowing for compensation of relative electrode position variations induced by thermo-mechanical stress, while maintaining sensitivity to inertial movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid coupling structures are used to connect stationary electrodes to anchors, then mechanical stability is improved, but thermo-mechanical stress causes offset and sensitivity drift in sensing output
Solution Approach 1:
The patent changes the mechanical parameter of the coupling structure from rigid to elastic, allowing it to deform under thermo-mechanical stress. This parameter change enables the structure to accommodate stress-induced dimensional changes without transmitting them to the stationary electrode, thereby maintaining sensing accuracy while preserving mechanical stability.
Solution Approach 2:
The patent introduces elastic elements (flexible coupling structures) to connect stationary electrodes to anchors. These flexible elements can deform elastically under thermo-mechanical stress, absorbing the stress-induced displacement and preventing it from affecting the electrode position and sensing output.
2Measurement precision
If elastic elements are incorporated into coupling structures, then compensation for thermo-mechanical stress is improved, but device complexity increases
Solution Approach 1:
The patent modifies the coupling structure by incorporating elastic elements with specific mechanical properties (elastic modulus, geometry). By carefully selecting these parameters, the structure achieves stress compensation functionality while maintaining manufacturing feasibility and avoiding excessive complexity.
Solution Approach 2:
The elastic element acts as an intermediary between the stationary electrode and the anchor. It mediates the stress transmission by deforming elastically under thermo-mechanical stress, thereby protecting the stationary electrode from stress-induced position changes while maintaining a relatively simple overall structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively compensates for thermo-mechanical stress-related offset and sensitivity drift, enhancing the performance of MEMS devices by adjusting the configuration, geometry, and number of elastic elements to mitigate stress impacts without compromising inertial sensing capabilities.
Implementation Method 1
Incorporating elastic elements into the coupling structures that connect stationary electrodes to anchors on a substrate, allowing for compensation of relative electrode position variations induced by thermo-mechanical stress
Data Source
AI summary
The invention relates to a microelectro-mechanical structure (MEMS), and more particularly, to systems, devices and methods of compensating effect of thermo-mechanical stress on a micro-machined accelerometer by incorporating and adjusting elastic elements to couple corresponding sensing electrodes. The sensing electrodes comprise moveable electrodes and stationary electrodes that are respectively coupled on a proof mass and a substrate. At least one elastic element is incorporated into a coupling structure that couples two stationary electrodes or couples a stationary electrode to at least one anchor. More than one elastic element may be incorporated. The number, locations, configurations and geometries of the elastic elements are adjusted to compensate an output offset and a sensitivity drift that are induced by the thermo-mechanical stress accumulated in the MEMS device.