Corrugated Diaphragm Sensor for High Sensitivity Pressure Detection
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Solution Overview
Problem
Conventional pressure sensors face challenges in achieving high sensitivity and signal-to-noise ratio, particularly in detecting low-intensity pressure fluctuations, while being robust against environmental contaminants and fluctuations, and require efficient fabrication processes.
Innovation Solution
A sensor design featuring a corrugated diaphragm offset from a substrate with a hermetically sealed near-vacuum cavity, where the diaphragm deflects responsive to sound waves, generating an electrical signal through capacitance or optical detection, and fabricated using CMOS or MEMS processes to control geometry and reduce residual stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional flat diaphragm is used in a pressure sensor, then the device structure is simple, but the sensitivity to low-intensity pressure fluctuations is insufficient and residual stress affects measurement precision
Solution Approach 1:
The patent applies corrugations (curved structures) to the diaphragm surface, transforming it from a flat plane to a corrugated structure. This curvature increases the diaphragm's sensitivity to pressure fluctuations while maintaining structural integrity and reducing residual stress, directly resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent modifies the diaphragm's geometric parameters by introducing corrugations with specific profiles and dimensions. These parameter changes enhance the diaphragm's mechanical properties, improving sensitivity to pressure changes while controlling residual stress, thereby achieving better measurement precision without excessive complexity.
2Measurement precision
If the diaphragm is positioned close to the substrate to increase sensitivity, then measurement precision improves, but the device becomes vulnerable to environmental contaminants
Solution Approach 1:
The patent extracts the sensitive detection function from the environment by creating a hermetically sealed cavity between the diaphragm and substrate. This cavity isolates the diaphragm from external contaminants while maintaining the close proximity needed for high sensitivity, effectively separating the detection mechanism from harmful environmental factors.
Solution Approach 2:
The patent creates an inert, hermetically sealed environment (vacuum or controlled atmosphere cavity) between the diaphragm and substrate. This inert environment protects the sensitive diaphragm from contaminants, moisture, and other harmful factors while allowing the diaphragm to operate at optimal sensitivity levels.
3Reliability
If a hermetically sealed cavity is introduced to protect against contaminants, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The patent merges the protective sealing function with the existing sensor structure by integrating the hermetic seal into the substrate-dia phragm assembly. This approach combines multiple functions (structural support, sensing, and protection) into a unified design, improving reliability while minimizing the increase in manufacturing complexity.
Solution Approach 2:
The patent uses thin-film fabrication techniques to create the hermetic seal and corrugated diaphragm structure. These thin films provide effective contamination protection while being compatible with standard semiconductor manufacturing processes, thereby improving reliability without significantly increasing manufacturing difficulty.
4Manufacturing precision
If standard fabrication processes are used, then manufacturing is straightforward, but control over diaphragm geometry and residual stress is insufficient
Solution Approach 1:
The patent segments the fabrication process into distinct stages (substrate preparation, corrugation formation, diaphragm deposition, cavity sealing) that can be integrated into existing CMOS or MEMS manufacturing lines. This segmentation allows precise control over diaphragm geometry and residual stress at each stage while maintaining compatibility with standard fabrication processes.
Solution Approach 2:
The patent employs composite material structures (multi-layer films, corrugated geometries) that provide enhanced control over diaphragm properties. These composite structures allow independent optimization of geometric parameters and stress characteristics while remaining manufacturable using advanced but standardized fabrication techniques.
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 design achieves high sensitivity and immediate response to low-intensity pressure fluctuations with reduced noise, robustness against contaminants, and compact, cost-effective fabrication, enabling consistent performance across varying environmental conditions.
Implementation Method 1
The deflection of the diaphragm can be detected by a change in a capacitance of the deflection structure
Implementation Method 2
A surface of the corrugated diaphragm facing the substrate is reflective. The substrate includes a light source positioned to illuminate the reflective surface of the corrugated diaphragm; and a detector configured to generate an electrical signal based on light reflected from the reflective surface of the corrugated diaphragm
Data Source
AI summary
A sensor includes a substrate; and a corrugated diaphragm offset from the substrate. The corrugated diaphragm is configured to deflect responsive to a sound wave impinging on the corrugated diaphragm. A cavity is defined between the corrugated diaphragm and the substrate, the corrugated diaphragm forming a top surface of the cavity and the substrate forming a bottom surface of the cavity. A pressure in the cavity is lower than a pressure outside of the cavity.