Temperature Gradient Method for Alleviating Bonding-Induced Warpage in a High-Precision Capacitive MEMS Accelerometer
Temperature Gradient Method for Alleviating Bonding-Induced Warpage in a High-Precision Capacitive MEMS Accelerometer
复制标题
用于减轻高精度电容式 MEMS 加速度计中键合引起的翘曲的温度梯度方法
DOI：
10.3390/s20041186
复制
发表时间：
2020-02-01
期刊：
影响因子：
3.9
通讯作者：
Tu, Liangcheng
中科院分区：
文献类型：
--
作者：
Liu, Dandan;Liu, Huafeng;Tu, Liangcheng
具有变面积周期性电极位移传感器的电容式MEMS加速度计在灾害监测、资源勘探和惯性导航等领域有着广泛的应用。由于键合片热膨胀系数的差异，键合引起的翘曲影响了电极间距的精确控制，而电极间距对加速度计的灵敏度至关重要。本文从理论、仿真和实验三个方面提出了一种通过施加不同的键合温度来同时减轻应力和翘曲的方法。实验证明了该方法的可行性，并实现了准零翘曲。由于表面平坦，电容位移传感器的间距可以精确控制，将加速度计的自噪声提高到6 ng/root Hz @0.07 Hz，比使用均匀温度键合工艺的加速度计的自噪声低约两倍。
Capacitive MEMS accelerometers with area-variable periodic-electrode displacement transducers found wide applications in disaster monitoring, resource exploration and inertial navigation. The bonding-induced warpage, due to the difference in the coefficients of thermal expansion of the bonded slices, has a negative influence on the precise control of the interelectrode spacing that is essential to the sensitivity of accelerometers. In this work, we propose the theory, simulation and experiment of a method that can alleviate both the stress and the warpage by applying different bonding temperature on the bonded slices. A quasi-zero warpage is achieved experimentally, proving the feasibility of the method. As a benefit of the flat surface, the spacing of the capacitive displacement transducer can be precisely controlled, improving the self-noise of the accelerometer to 6 ng/root Hz @0.07 Hz, which is about two times lower than that of the accelerometer using a uniform-temperature bonding process.