A Reliability Analysis of a MEMS Flow Sensor with an Accelerated Degradation Test

Area of Science:

• Materials Science
• Electrical Engineering
• Mechanical Engineering

Background:

• Micro Electro Mechanical Systems (MEMS) flow sensors are widely used, but their reliability under extreme temperatures is a growing concern.
• Understanding sensor degradation is crucial for ensuring performance in demanding applications.

Purpose of the Study:

• To assess the reliability of a MEMS flow sensor, specifically its sensor chip and signal-processing system (SPS), under varying temperature conditions.
• To establish predictive models for sensor lifetime and reliability using accelerated degradation testing.

Main Methods:

• Step-stress accelerated degradation test (SSADT) was performed on the sensor chip and the complete flow sensor system.
• The Coffin-Manson model was used to establish the relationship between thermal cycling and temperature.
• Arrhenius model and Weibull distribution (WD) were applied to estimate sensor lifetime and reliability.

Main Results:

• The signal-processing system (SPS) was found to be the primary contributor to flowmeter degradation, accounting for at least 82.01% of the drift.
• Sensor chips showed a maximum drift of 3.15% at 150 °C, while the complete flowmeter system exhibited a drift of 32.91%.
• The estimated survival rate for the flow sensor within one year at 85 °C was 87.69%.

Conclusions:

• The signal-processing system's reliability is critical for the overall performance and longevity of MEMS flow sensors.
• Accelerated degradation testing provides valuable data for predicting sensor lifetime and ensuring reliability in high-temperature environments.
• This research establishes a foundation for future reliability studies and provides a database for MEMS flow sensor applications.