多层陶瓷电容器的简化有限元模型及失效分析

Simplified Finite Element Model for Thermal Residual Stress in Multilayer Ceramic Capacitors

基于弹塑性有限元法计算了不同厚度介质层的多层陶瓷电容(MLCC)在制备过程中引发的残余应力,并分析了其失效机理。通过采用MLCC的简化模型对器件的多层结构进行简化,从而有效避免了高层数和完全三维模型计算量大等缺点。结果表明:陶瓷层和电极层的相对厚度决定了残余应力的大小,在其相对厚度值中存在一个临界值,在临界值附近其残余应力的变化趋势相反;同时器件在制备过程中产生的热应力将导致器件的内电极端部附近开裂。

The failure mechanisms of muhilayer ceramic capacitors （MLCC） due to thermal residual stress were analyzed by using elastic plastic finite element （FE） method. A simplified FE model was proposed to take into account the effect of multilayer structure, which can avoid the multilayer structure design and reduce the computational cost. The results obtained from this simplified FE show that there exists a critical thickness ratio of the electrode layer to the dielectric layer in MLCC, below and above which the change trends of the residual stress are opposite. Meanwhile, a fracture mechanics analysis has also been conducted, and the simulation results show the interfacial cracks are more likely to initiate and propagate at the tip end of the inner electrodes.