高功率密度电源模块磁芯粘接的工艺可靠性

Reliability of Magnetic Core Bonding for New High Density Power Module

新型高功率密度电源模块采用芯片塑封的工艺方式,实现磁芯、元器件、印制板(PCB)和塑封料的一体式封装。磁芯设计采用绕组内置在印制板内部,并采用扁平磁芯装配的方式实现磁芯的电气功能。由于磁芯材料、粘接材料和印制板之间的材料性能不匹配,环境试验中产生的粘接内应力过大会直接造成磁芯材料产生裂纹甚至断裂失效,严重影响了电源产品的可靠性。主要聚焦于磁芯粘接工艺,分析磁芯粘接内应力产生的机理,通过有限元数值分析手段,得出磁芯材料在周期性的热载荷条件下的应力分布情况,最后通过仿真分析和试验验证,选出最优的磁芯粘接材料和合理的粘接工艺参数,为选择合适的磁芯粘接材料和优化粘接工艺参数提供了参考依据。

The new high-density power module adopts the process of chip plastic packaging to realize the integrated packaging of magnetic core,components,PCB and plastic packaging material.The magnetic core is designed with the winding built in the PCB,and the electrical function of the magnetic core is realized by means of flat magnetic core assembly.Due to the material performance mismatch between the magnetic core material,adhesive material and PCB,the excessive bonding internal stress generated in the environmental test directly causes the crack or even fracture failure of the magnetic core material,which seriously affects the reliability of the power module products.Mainly focusing on the magnetic core adhesive process,the mechanism of internal stress in magnetic core is analyzed.The stress distribution of magnetic core material under periodic thermal load is numerically analyzed by finite element method.Fin ally,the optimal magnetic core adhesive material and reasonable adhesive process parameters are selected through simulation analysis and experimental verification,which provides a reference basis for selecting appropriate magnetic core adhesive material and optimizing adhesive process parameters.