Low cost MEMS Accelerometer
Accelerometers are a typical type of inertial sensor, with wide and important applications in aviation, aerospace, navigation, weaponry, and civilian fields. However, the large size and high cost of traditional accelerometers limit their applications. With the development of Micro-Electro-Mechanical System (MEMS) technology, various MEMS accelerometers with small size, low power consumption, and wide application range have emerged.
In addition to the all-silicon structure, there are other measures to improve the overall temperature performance of MEMS accelerometers. Firstly, by effectively reducing the thermal stress transmitted to the sensitive structure through the stress elimination method proposed in the previous section, the overall temperature performance of the accelerometer is improved. Secondly, through the study of low-stress bonding parameters, low-stress stacking and packaging of MEMS accelerometers are achieved. Based on this, further improvement of the overall temperature performance of the accelerometer is achieved through third-order temperature compensation for accelerometer bias and scale factor.
1.Low-stress bonding process design
In order to reduce the packaging volume of MEMS accelerometers, this paper does not adopt the traditional method of packaging two chips flatly. Instead, it adopts a stacked packaging design with MEMS sensitive structures and Application Specific Integrated Circuit (ASIC) chips, as shown in Figure 1.