MEMS Calibration via ASIC Strain Gauges
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Solution Overview
Problem
Microelectromechanical systems (MEMS) devices face mechanical stresses during soldering and substrate attachment, which affect the physical properties of MEMS components, such as elasticity and capacitive gaps, leading to calibration challenges.
Innovation Solution
Incorporating piezoresistive strain gauges in the ASIC semiconductor substrate, which are doped semiconductor regions that measure strain and provide output values for a trim algorithm, allowing for effective calibration of MEMS components without complicating their manufacture or operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoresistive strain gauges are incorporated into the MEMS substrate, then strain measurement accuracy is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent introduces a separate ASIC substrate as an intermediary carrier for the piezoresistive strain gauges, which measures strain in the ASIC and transmits this data to the MEMS device. This mediator approach allows strain measurement without directly modifying the MEMS substrate, thus maintaining measurement accuracy while reducing complexity and manufacturing difficulty of the MEMS component itself.
2Measurement precision
If piezoresistive strain gauges are incorporated into the MEMS substrate, then strain measurement accuracy is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent segments the strain measurement function from the MEMS device by placing piezoresistive strain gauges on a separate ASIC substrate. This segmentation allows the MEMS device to be manufactured using standard processes while the strain measurement capability is provided by the ASIC, which can be manufactured separately and then integrated, thereby improving ease of manufacture while maintaining measurement accuracy.
3Measurement precision
If stiff attachment between substrates is used, then strain transfer accuracy is improved, but mechanical stress on MEMS components increases
Solution Approach 1:
The patent uses the ASIC substrate as a mediator that can be attached to the MEMS substrate with varying degrees of stiffness. The piezoresistive strain gauges on the ASIC measure the strain experienced by the ASIC itself, which serves as a proxy for the strain on the MEMS device. This intermediary approach allows for accurate strain transfer measurement while providing flexibility in attachment design to minimize mechanical stress on sensitive MEMS components.
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
The solution enables accurate strain measurement and calibration of MEMS devices, improving the accuracy and consistency of readings by accounting for mechanical stresses, thereby maintaining the integrity of MEMS components' physical properties.
Implementation Method 1
at least one piezoresistive strain gauge, each piezoresistive strain gauge comprising at least one doped semiconductor region having a resistivity that is determined by a strain on said doped semiconductor region
Data Source
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AI summary
A microelectromechanical systems (MEMS) device and a method for calibrating a MEMS device. The device includes a first semiconductor substrate including at least one MEMS component. The device also includes an application specific integrated circuit (ASIC) comprising a second semiconductor substrate. The second semiconductor substrate is attached to the first semiconductor substrate. The second semiconductor substrate includes at least one piezoresistive strain gauge. Each piezoresistive strain gauge includes at least one doped semiconductor region having a resistivity that is determined by a strain on said doped semiconductor region. The second semiconductor substrate also includes a circuit for evaluating a trim algorithm for the at least one MEMs component using one or more output values received from the at least one piezoresistive strain gauge.