MEMS Microphone Diaphragm Spring Structure for Stress Dissipation
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Solution Overview
Problem
Piezosensitive MEMS microphone components face mechanical stress issues due to larger diaphragm areas, which affect signal quality and power consumption, especially in 'always-on' mode, and are sensitive to temperature variations.
Innovation Solution
A three-dimensional spring structure is implemented, with components oriented parallel and perpendicular to the diaphragm, allowing for larger diaphragm areas without additional chip space, and featuring ventilation openings for pressure equalization, to dissipate mechanical stresses and improve sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the diaphragm area is increased to improve microphone sensitivity, then sensitivity is improved, but mechanical stresses within the diaphragm increase which corrupt the measuring signal
Solution Approach 1:
The spring structure is extended into the third dimension (vertical direction perpendicular to the diaphragm plane) with a second spring component that connects the diaphragm edge to the substrate. This three-dimensional configuration allows the diaphragm to have a larger area while providing additional stress relief paths through the vertical spring component, preventing mechanical stress accumulation that would otherwise corrupt the measurement signal.
2Measurement precision
If the diaphragm area is increased to improve sensitivity, then sensitivity is improved, but the chip area required increases
Solution Approach 1:
The spring structure utilizes the vertical dimension (third dimension) to connect the diaphragm to the substrate, allowing the diaphragm area to exceed the opening area. The second spring component extends vertically from the diaphragm edge to the substrate, enabling larger diaphragm areas without proportionally increasing the chip footprint, thus maintaining sensitivity improvement while controlling chip area.
3Device complexity
If a two-dimensional spring structure is used in the diaphragm plane, then the structure is simple, but it cannot accommodate diaphragm elements larger than the opening area
Solution Approach 1:
The spring structure transitions from a two-dimensional planar configuration to a three-dimensional structure by adding a second spring component that extends vertically perpendicular to the diaphragm plane. This vertical extension allows the diaphragm area to be larger than the opening area while maintaining structural integrity and providing necessary mechanical support, overcoming the limitations of two-dimensional spring designs.
4Measurement precision
If the diaphragm area is increased to improve sensitivity, then sensitivity is improved, but power consumption in always-on mode increases
Solution Approach 1:
The three-dimensional spring structure with the vertical second spring component provides enhanced mechanical stress relief and structural stability, enabling the diaphragm to operate with larger area (improved sensitivity) while reducing the need for continuous power consumption in always-on mode by improving the efficiency of the piez sensitive detection system.
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
This design enhances microphone sensitivity, improves signal-to-noise ratio, and reduces power consumption by managing mechanical stresses and temperature variations, making the components more efficient and robust.
Implementation Method 1
The relaxation of the diaphragm element thus takes place here in all three spatial directions
Implementation Method 2
with equipment with piezosensitive circuit elements for signal detection
Data Source
AI summary
Measures are provided, by which mechanical stresses within the diaphragm structure of a MEMS component may be intentionally dissipated, and which additionally enable the implementation of diaphragm elements having a large diaphragm area in comparison to the chip area. The diaphragm element is formed in the layer structure of the MEMS component. It spans an opening in the layer structure and is attached via a spring structure to the layer structure. The spring structure includes at least one first spring component, which is oriented essentially in parallel to the diaphragm element and is formed in a layer plane below the diaphragm element. Furthermore, the spring structure includes at least one second spring component, which is oriented essentially perpendicularly to the diaphragm element. The spring structure is designed in such a way that the area of the diaphragm element is greater than the area of the opening which it spans.