摘要
MEMS加速度计等传感器检测精度受机械元件加工、电路制作、封装工艺等方面影响,其中机械热应力的影响尤为显著。为降低热应力,提出了一种基于多层嵌套环驻波特性的应力隔离结构设计,利用嵌套环的驻波振动特性,通过多层嵌套环逐级吸收传递至敏感结构的能量,从而达到隔离锚点处热应力的效果。通过有限元方法计算了不同嵌套环在热应力下变形情况,并研究了键合残余热应力与温度变化热应力对加速度计敏感结构频率、正应力和切应力的影响规律,得出在不同结构布局和尺寸参数下设计的应力隔离效率。对于正应力而言,应力隔离效率最优可以达到99.98%;对于切应力而言,应力隔离效率最优可以达到99.53%。结果表明,多层嵌套环应力隔离结构在特定布局和尺寸条件下的应力隔离效果优于现有的框架式应力隔离结构。
The performance of MEMS sensors such as accelerometer is high dependent on the fabrication of the mechanical component and the readout circuit,the packaging process and so on.In particular,the thermal stress effect of the mechanical structure of MEMS sensors is dominant.To reduce the thermal stress,a novel stress-isolation structure utilizing the standing wave characteristics of concentric rings is proposed.The thermal stress resulted from the anchors can be absorbed by the concentric-ring structure and thus isolated from the sensitive structure.Based on finite element method(FEM),the thermal deformation is evaluated for different concentric-ring structures.The effects of both the residual stress arising from the anodic bonding process and the thermal stress due to temperature change on the resonant frequency and normal/shear stress of the accelerometer are revealed.The efficiency of stress isolation is estimated for different concentric-ring structural designs.It shows that the efficiencies of the normal and shear stress isolation exceed 99.98%and 99.53%respectively.As a result,the concentric-ring structure with optimized structural dimension has superior stress-isolation performance over the conventional frame-type structure.
作者
董磊锘
马志鹏
陈瑾亮
DONG Leinuo;MA Zhipeng;CHEN Jinliang(School of Aeronautics and Astronautics,Zhejiang University,Hangzhou Zhejiang 310027,China)
出处
《传感技术学报》
CAS
CSCD
北大核心
2023年第2期167-173,共7页
Chinese Journal of Sensors and Actuators
基金
国家自然科学基金委员会青年科学基金项目(62104211)。
关键词
MEMS
应力隔离
有限元分析
微加速度计
热应力
MEMS
stress isolation
finite element analysis
micro-accelerometer
thermal stress
