Zhou Wu, Peng Peng, Yu Huijun, Peng Bei, He Xiaoping
School of Mechatronics Engineering, University of Electronic Technology and Science of China, Chengdu 611731, China.
Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, China.
Materials (Basel). 2017 Sep 14;10(9):1077. doi: 10.3390/ma10091077.
Polymer-based materials are commonly used as an adhesion layer for bonding die chip and substrate in micro-system packaging. Their properties exhibit significant impact on the stability and reliability of micro-devices. The viscoelasticity, one of most important attributes of adhesive materials, is investigated for the first time in this paper to evaluate the long-term drift of micro-accelerometers. The accelerometer was modeled by a finite element (FE) method to emulate the structure deformation and stress development induced by change of adhesive property. Furthermore, the viscoelastic property of the adhesive was obtained by a series of stress-relaxation experiments using dynamic mechanical analysis (DMA). The DMA curve was imported into the FE model to predict the drift of micro-accelerometers over time and temperature. The prediction results verified by experiments showed that the accelerometer experienced output drift due to the development of packaging stress induced by both the thermal mismatch and viscoelastic behaviors of the adhesive. The accelerometers stored at room temperature displayed a continuous drift of zero offset and sensitivity because of the material viscoelasticity. Moreover, the drift level of accelerometers experiencing high temperature load was relatively higher than those of lower temperature in the same period.
基于聚合物的材料通常用作微系统封装中芯片与基板键合的粘附层。它们的性能对微器件的稳定性和可靠性有显著影响。本文首次研究了粘性材料最重要的属性之一——粘弹性，以评估微加速度计的长期漂移。通过有限元（FE）方法对加速度计进行建模，以模拟由粘性属性变化引起的结构变形和应力发展。此外，通过使用动态力学分析（DMA）的一系列应力松弛实验获得了粘合剂的粘弹性属性。将DMA曲线导入FE模型，以预测微加速度计随时间和温度的漂移。经实验验证的预测结果表明，由于粘合剂的热失配和粘弹性行为引起的封装应力发展，加速度计经历了输出漂移。由于材料的粘弹性，存储在室温下的加速度计显示出零偏移和灵敏度的持续漂移。此外，在同一时期，经历高温负载的加速度计的漂移水平相对高于低温下的加速度计。
