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以一种新型高G值MEMS加速度传感器为例进行有限元模拟,将实际封装简化为一种最简单的封装结构,进行频域分析和时域分析,讨论粘结传感器芯片和封装基体的封接材料对其输出信号的影响。频域分析表明,封接材料的杨氏模量对封装后加速度传感器整体的振动模态的影响很大,封接胶的杨氏模量很小时会致使加速度传感器的信号失真,模拟表明可选用杨氏模量足够高的环氧树脂类作高G值传感器的封接材料。时域分析静态模拟表明,封接材料的杨氏模量对最大等效应力、最大正应力以及沿加载垂直方向的正应力的最大值与最小值基本无影响。时域分析动态模拟表明,随着封接材料杨氏模量的提高,动态模拟输出的悬臂梁末端节点位移的波形和经数字滤波后输出的信号变好,封接材料的杨氏模量不影响输出信号的频率和均值,在加速度脉冲幅值输入信号变化时,悬臂梁末端位移平均值输出信号与输入有良好的线性关系。
Taking a new type of high-G MEMS acceleration sensor as an example, finite element simulation is carried out to simplify the actual package into one of the simplest package structures. The frequency domain analysis and time domain analysis are carried out to discuss the bond between the bonded sensor chip and the package substrate The effect of material on its output signal. The frequency domain analysis shows that the Young’s modulus of the sealing material has a great influence on the vibration modes of the accelerometer after encapsulation. When the Young’s modulus of the sealant is small, the signal of the accelerometer will be distorted, and the simulation shows that it can be used Epoxy resins with high Young’s modulus are high-G-value sealing materials. Time-domain analysis of static simulation shows that the Young’s modulus of the sealing material has no effect on the maximum equivalent stress, the maximum normal stress and the maximum and minimum normal stresses along the vertical direction of loading. Dynamic simulation of time-domain analysis shows that with the increase of the Young’s modulus of the sealing material, the waveforms at the end nodes of the dynamic simulation output cantilever and the signals output after digital filtering become better, the Young’s modulus of the sealing material is not Affect the frequency and average value of the output signal. When the input signal of the acceleration pulse amplitude changes, the output value of the average displacement of the end of the cantilever beam has a good linear relationship with the input.