Calibration-Free, Split Accelerated Degradation Testing Platform Revealing the Long-Term Reliability of 2-D Micromirrors Without On-Chip Sensors

Abstract

Complicated multi-failure mechanisms triggered by distinctive stresses in different harsh environments have become essential yet challenging in reliability research of microelectromechanical systems (MEMS). For this issue, accelerated degradation testing (ADT) is widely used as an efficient strategy to obtain the long-term reliability of MEMS devices in a short amount of time. Therefore, precise and robust monitoring of performance degradation in harsh environments is the foundation of ADTs. However, current electro-mechanical-coupling methods, especially on-chip piezoresistive sensors, exhibit sensitivity shifts and must be calibrated manually at different temperatures, making them costly and restricting the accuracy. Here, we propose a calibration-free, temperature-robust split accelerated degradation testing platform (S-ADTP), which can accurately evaluate the long-term reliability of 2D MEMS micromirrors without any thermal-induced sensitivity shifts. S-ADTP eliminates the error of the FOV detection caused by sensitivity shifts, contributing to higher and more temperature-robust accuracy than electro-mechanical-coupling methods. ADTs with single and multiple stresses are subsequently conducted. Experimental results reveal the distinct failure mechanisms associated with varying environmental conditions, indicating that the crack propagation is the primary failure mode in high-temperature environments, while the demagnetization of permanent magnets becomes dominant in temperature-humidity coupling environments. The work can provide a calibration-free and temperature-robust method without any thermal-induced sensitivity shifts in ADTs for 2D micromirrors, and distinguish the complicated multi-failure mechanisms triggered by distinctive environmental stresses.[2025-0062]