Reliability Evaluation Based on Mathematical Degradation Model for Vacuum Packaged MEMS Sensor

Abstract

Vacuum packaging is used extensively in MEMS sensors for improving performance. However, the vacuum in the MEMS chamber gradually degenerates over time, which adversely affects the long-term performance of the MEMS sensor. A mathematical model for vacuum degradation is presented in this article for evaluating the degradation of vacuum packaged MEMS sensors, and a temperature-accelerated test of MEMS gyroscope with different vacuums is performed. A mathematical degradation model is developed to fit the parameters of the degradation of Q-factor over time at three different temperatures. The results indicate that the outgassing rate at 85 °C is the highest, which is 0.0531 cm2/s; the outgassing rate at 105 °C is the lowest, which is 0.0109 cm2/s; and the outgassing rate at 125 °C is in the middle, which is 0.0373 cm2/s. Due to the different mechanisms by which gas was released, the rate of degradation did not follow this rule. It will also be possible to predict the long-term reliability of vacuum packaged MEMS sensors at room temperature based on this model.

Parametric Analysis of Electrostatic Comb Drive for Resonant Sensors Operating under Atmospheric Pressure

“…Table 1 illustrates the structural parameters and reference values of the microresonator. According to Equation (10), the capacitance change rate (or the electrostatic force) is proportional to the film thickness h. Additionally, the capacitance change rate is influenced by the comb finger width, the comb finger gap, the lateral distance between the comb fingers, and the length of the overlapping section of the comb fingers. Consequently, while computing the capacitance change rate, these five parameters are swept from 67% to 167% of their reference values; the resulting calculation is depicted in Figure 3.…”

“…Due to its low power consumption, compatibility with complementary metal oxide semiconductor processes, ease of downsizing, and electronic control, the electrostatic comb drive structure has become one of the most widely used drive mechanisms in MEMS. Due to the issues of high fabrication and maintenance costs, high technical level requirements, low reliability, and short life of vacuum packaging [8][9][10], electrostatic comb drive for resonant sensors like gyroscopes [11][12][13], magnetic field strength sensors [14], resonant micromirrors [15,16], and electric field sensors [2,3] are operating at atmospheric pressure. In addition, some special microelectrostatic resonators, such as ultrasonic transducers [17], can only function under normal pressure.…”

Research on Packaging Reliability and Quality Factor Degradation Model for Wafer-Level Vacuum Sealing MEMS Gyroscopes

“…The microelectromechanical system (MEMS) represents a sophisticated microintelligent system that leverages microelectronics, micromechanics, and related technologies to integrate sensors, actuators, and signal transmission components [1]. MEMS sensors exhibit key attributes such as compact size, lightweight design, and cost-effectiveness, and they are on the brink of achieving passive operation, miniaturization, and immunity to interference [2]. With the relentless progression of technology, MEMS sensors have found widespread utility across various domains, including consumer electronics, aerospace, military equipment, biomedicine, and more [3].…”

Editorial for the Special Issue on Advanced Interconnect and Packaging

“…Zheng et al study the average power handling capability of corrugated slow-wave transmission lines [ 9 ]. Du et al develop a mathematical degradation model for evaluating the degradation of vacuum packaged MEMS sensors and perform a temperature-accelerated test of MEMS gyroscopes with different vacuums [ 10 ]. Zhao et al introduce recent studies on the physics-based modeling of the electromigration aging of interconnects [ 11 ].…”