A High-Q Resonant Pressure Microsensor with Through-Glass Electrical Interconnections Based on Wafer-Level MEMS Vacuum Packaging
Citation
Luo, Z.; Chen, D.; Wang, J.; Li, Y.; Chen, J. A High-Q Resonant Pressure Microsensor with Through-Glass Electrical Interconnections Based on Wafer-Level MEMS Vacuum Packaging. Sensors 2014, 14, 24244–24257.
- resonant pressure sensor
- through-glass via (TGV)
- anodic bonding
- wafer-level vacuum packaging
- getter material
- Q-factor
- SOI wafer
- differential structure
Brief
This article presents a highly sensitive resonant pressure microsensor that leverages wafer-level vacuum packaging with through-glass electrical interconnections to achieve high performance.
Summary
This article, published in 2014 in the journal Sensors, describes the design, fabrication, and characterization of a highly sensitive resonant pressure microsensor.
Here are the key takeaways:
- The microsensor utilizes a differential design based on two "H" type doubly-clamped micro resonant beams suspended on a pressure-sensitive diaphragm. When pressure is applied, one beam experiences tensile stress while the other experiences compressive stress, leading to a shift in their resonant frequencies. This differential output improves sensitivity and reduces the impact of temperature variations.
- The fabrication process leverages wafer-level MEMS vacuum packaging, specifically silicon-to-glass anodic bonding, to create a sealed vacuum chamber for the resonator. This packaging technique ensures long-term vacuum tightness and protects the delicate resonant beams.
- Through-glass vias (TGVs) enable electrical connections to the resonator from the outside, simplifying the integration and packaging process.
- A non-evaporable metal thin film acts as a getter material inside the vacuum chamber. This getter material absorbs residual gases, further enhancing the vacuum and improving the Q-factor of the resonator.
- Testing demonstrates the effectiveness of the design, with the microsensor achieving high performance metrics:
- High Q-factor: Exceeding 22,000, indicating minimal energy loss and high sensitivity.
- High sensitivity: Differential sensitivity of 89.86 Hz/kPa, enabling the detection of minute pressure changes.
- Low nonlinearity: 0.02% F.S. over a 50 kPa to 100 kPa pressure range.
- Low temperature drift: Less than -0.01% F.S./°C from -40°C to 70°C, demonstrating stability across a wide temperature range.
- Excellent long-term stability: 0.01% F.S. drift over a 5-month period.
- High accuracy: Better than 0.01% of full scale.
The authors conclude that this resonant pressure microsensor, with its high sensitivity, accuracy, and stability, is a promising candidate for applications requiring precise pressure measurements.
Origin: https://www.semanticscholar.org/reader/1f5d42cee449c93ad01aec61c7a2ce43df099bdd