Wang Jingchen, Liu Heng, Li Zhi
School of Electronics and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
Sensors (Basel). 2025 Jul 24;25(15):4583. doi: 10.3390/s25154583.
To develop solutions to the frequency instability and failure of silicon micromechanical resonant accelerometers, the state characteristics of micromechanical resonant accelerometers are investigated under temperature and vibration stresses. Through theoretical analysis and finite element simulation, the following is found: the Young's modulus of silicon varies with temperature, causing a resonance frequency shift of -1.364 Hz/°C; the residual stress of temperature change affects the resonance frequency shift of the microstructure, causing it to be 5.43 Hz/MPa (tensile stress) and -5.25 Hz/MPa (compressive stress); thermal expansion triggers the failure of the bonding wire, and, in the range of 10 °C to 150 °C, the peak stress of the electrode/lead bond area increases from 83.2/85.6 MPa to 1.08/1.28 GPa. The failure mode under vibration stress is resonance structure fracture and interlayer peeling. An isolation frame design is proposed for the sensitive part of the microstructure, which reduces the frequency effects by 34% (tensile stress) and 15% (compressive stress) under temperature-variable residual stresses and the maximum value of the structural root mean square stresses by 69.7% (X-direction), 63.6% (Y-direction), and 71.3% (Z-direction) under vibrational stresses.
为了开发解决硅微机械谐振加速度计频率不稳定和失效问题的方案，研究了微机械谐振加速度计在温度和振动应力作用下的状态特性。通过理论分析和有限元模拟，发现以下情况：硅的杨氏模量随温度变化，导致共振频率偏移为-1.364Hz/°C；温度变化引起的残余应力影响微结构的共振频率偏移，使其为5.43Hz/MPa（拉应力）和-5.25Hz/MPa（压应力）；热膨胀引发键合线失效，在10°C至150°C范围内，电极/引线键合区域的峰值应力从83.2/85.6MPa增加到1.08/1.28GPa。振动应力下的失效模式为共振结构断裂和层间剥离。针对微结构的敏感部分提出了一种隔离框架设计，在温度变化残余应力下，该设计使频率效应降低了34%（拉应力）和15%（压应力），在振动应力下，结构均方根应力的最大值在X方向降低了69.7%，在Y方向降低了63.6%，在Z方向降低了71.3%。
