MEMS Shielded Capacitive Pressure and Force Sensors with Excellent Thermal Stability and High Operating Temperature

Area of Science:

• Materials Science
• Sensor Technology
• Mechanical Engineering

Background:

• High-temperature applications require robust sensors with excellent thermal stability.
• Conventional pressure and force sensors often face limitations in extreme temperature environments.
• Miniaturized and shielded sensors are crucial for advanced industrial and scientific applications.

Purpose of the Study:

• To present an innovative manufacturing process for capacitive pressure and force sensors.
• To achieve excellent thermal stability for high-temperature applications (up to 500 °C).
• To enable a wide measuring range (mN to kN) with customizable sensor dimensions.

Main Methods:

• Utilizing a stack of two silicon chips.
• Employing gold-silicon (Au-Si) or aluminum-silicon (Al-Si) eutectic bonding.
• Implementing shielding and miniaturization techniques.

Main Results:

• Sensors demonstrate excellent thermal stability up to 500 °C.
• Achieved high linearity of 99.992% FS at 350 °C.
• Exhibited low temperature drift (-0.001% FS/K at 350 °C) and nonlinearity (0.035% FS at 500 °C).

Conclusions:

• The innovative manufacturing process yields high-performance capacitive sensors for extreme temperatures.
• The sensors offer a unique combination of wide measuring range, thermal stability, and accuracy.
• This technology is suitable for demanding high-temperature sensing applications.