Temperature Gradient Method for Alleviating Bonding-Induced Warpage in a High-Precision Capacitive MEMS Accelerometer

Dandan Liu, Huafeng Liu, Jinquan Liu, Fangjing Hu, Ji Fan, Wenjie Wu*, and Liangcheng Tu*

Capacitive MEMS accelerometers with area-variable periodic-electrode displacement transducers have 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 negative influence on the precise control of the interelectrode spacing that is essential to the sensitivity of accelerometers. In this work, we proposed the theory, simulation and experiment of a method that can alleviate both the stress and warpage by applying different bonding temperature on the bonded slices. A quasi-zero warpage is achieved experimentally, proving the feasibility of the method. Beneficial from the flat surface, the spacing of the capacitive displacement transducer can be precisely controlled, improving the self-noise of the accelerometer to 6 ng/√Hz @0.07 Hz, which is about 2 times lower than that of the accelerometer using a uniform-temperature bonding process.

期刊名：Sensors

期/卷：20/1168

页码：1-12

发表时间：2020年2月

DOI:10.3390/s20041186