封装粘接层空洞对微加速度计温漂的影响

发布时间：2019-01-21 09:13

【摘要】：叉指式微加速度计的应用领域涉及到娱乐生活、国防事业等方面,是微传感器中重要的研究对象之一。在其使用过程中,由于环境温度变化引起的输出漂移现象是影响微加速度计的测试精度的主要因素之一。温漂的产生是由于微加速度计封装结构在环境温度变化时发生了变形,粘接层空洞是造成这种变形的主要因素之一。随着对微加速度计精度要求越来越高,由粘接层空洞引起封装结构的变形对输出温漂的影响不可忽略。目前,国内外关于粘接层空洞的研究主要分析空洞对封装结构热学方面的影响,封装结构变形或输出温漂受空洞影响的研究很少。因此,为了提高微加速度计的测试精度,有必要分析封装粘接层空洞对微加速度计温漂的影响。本文将封装粘接层空洞对微加速度计温漂的影响分解为两个步骤进行研究,首先分析粘接层空洞对封装结构的影响,在此基础上分析封装结构对微加速度计温漂的影响。主要内容有:1.分析粘接层空洞对封装结构的影响,该过程中同时采用理论与仿真进行计算。仿真的封装结构模型在ANSYS有限元软件中建立,粘接层空洞的结构使用“生死单元”技术生成。理论计算采用结构分析理论进行封装结构的分析,并使用微分方程的标准求解法进行求解。比较仿真与理论计算所得的界面切应力可知,在粘接层不带空洞和带空洞的情况下,仿真模型都可以准确计算出封装结构冷却变形后的情形。2.分析封装结构变形对微加速度计输出温漂的影响,该过程也同时采用理论与仿真进行计算,利用冷却变形后微加速度计锚点在敏感方向上的位移求出输出温漂。比较理论计算与仿真计算所得的数据可知,两种计算方法都可以通过锚点的位移准确计算出微加速度计输出温漂。另外,分析锚点在非敏感方向上的位移对微加速度计输出温漂的影响可知,非敏感方向的影响很小,可忽略不计。3.在前面两部分研究的基础上,分析粘接层空洞对微加速度计输出温漂的影响。粘接层空洞与粘接层中心的距离的增大会使得输出温漂呈现上升-下降-上升的变化趋势,粘接层空洞的增大会使得输出温漂持续增大,而粘接层中两个空洞共同作用时的输出温漂近似等于该两空洞单独作用时输出温漂的累加和。
[Abstract]:The application of cross-finger micro-accelerometer is one of the most important research objects in micro-sensor, which involves entertainment, national defense and so on. The output drift caused by the change of ambient temperature is one of the main factors that affect the measuring accuracy of microaccelerometer. The temperature drift is caused by the deformation of the microaccelerometer packaging structure when the ambient temperature changes. The bonding layer cavity is one of the main factors causing the deformation. As the precision of micro-accelerometers is higher and higher, the effect of the deformation of the packaging structure caused by the cavity in the bonding layer on the output temperature drift can not be ignored. At present, at home and abroad, the effect of the cavity on the thermal properties of the packaging structure is mainly analyzed, and the effect of the cavity on the deformation of the package structure or the output temperature drift is seldom studied. Therefore, in order to improve the precision of microaccelerometer, it is necessary to analyze the effect of the cavity in the package bonding layer on the temperature drift of the micro-accelerometer. In this paper, the effect of bonding layer cavity on temperature drift of microaccelerometer is divided into two steps. Firstly, the effect of bonding layer cavity on package structure is analyzed, and then the effect of package structure on temperature drift of micro-accelerometer is analyzed. The main contents are: 1. The influence of bonding layer cavity on the package structure is analyzed, and the theory and simulation are used in the process. The simulated encapsulation structure model is established in the ANSYS finite element software, and the cavity structure of the bonding layer is generated by the "birth and death element" technique. The structure analysis theory is used to analyze the package structure, and the standard solution method of differential equation is used to solve the problem. By comparing the interfacial shear stress obtained by simulation and theoretical calculation, it can be seen that the simulation model can accurately calculate the cooling deformation of the packaging structure without the cavity and the cavity in the bonding layer. 2. The effect of package structure deformation on the temperature drift of microaccelerometer output is analyzed. At the same time, the temperature drift of micro-accelerometer output is obtained by using the displacement of anchor point of micro-accelerometer in sensitive direction after cooling deformation. Compared with the data obtained by theoretical calculation and simulation calculation, both methods can accurately calculate the output temperature drift of the micro-accelerometer by the displacement of the anchor point. In addition, the influence of the displacement of anchor point on the temperature drift of the micro-accelerometer output in the non-sensitive direction is analyzed. The influence of the non-sensitive direction on the output temperature drift of the micro-accelerometer is very small and negligible. On the basis of the first two parts, the effect of bonding layer cavity on the temperature drift of micro accelerometer output is analyzed. The increase of the distance between the cavity of the bonding layer and the center of the bonding layer will make the output temperature drift show a trend of rising, descending and rising, and the increase of the cavity in the adhesive layer will make the output temperature drift increase continuously. The output temperature drift is approximately equal to the sum of the output temperature drift when the two voids act alone in the bonding layer.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH824.4

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