关键词: 多层瓷介电容器, 板弯失效, 高低温环境, 开裂失效

Abstract: Multilayer ceramic capacitors (MLCC) are among the most widely used passive components in modern electronic systems. However, excessive bending of printed circuit boards can cause fracture of the brittle ceramic dielectric within MLCC, where crack propagation through the internal electrodes may result in electrical short circuits. To investigate this failure phenomenon, this study employs Surface Evolver to generate realistic solder geometries and applies a homogenization method of composite materials to equivalently simplify the active region of the MLCC. A three-dimensional thermo-mechanical coupled finite element model is developed to simulate the bending stress distribution of three types of MLCC under five temperature conditions (−25 ℃, 0 ℃, 25 ℃, 50 ℃, and 80 ℃). In addition, bending experiments under high and low temperature conditions are conducted. The experimental results show good agreement with the FEM predictions in terms of both failure strain and crack initiation locations, validating the accuracy of finite element model. The study indicates that, compared with high temperature condition, MLCC are more prone to cracking at low temperatures and exhibit smaller bending failure strains.

Key words: multilayer ceramic capacitor, flex failure, high and low temperature conditions, fracture failure