面向引线框架封装的热阻建模与分析

Modeling and analysis of thermal resistance for lead frame package

针对通用的QFP48引线框架封装,首先探讨了封装中的热传输机制,给出了热阻的理论计算结果;接着利用Ansys Icepak软件建立起QFP48的有限元模型,热阻仿真结果较好地验证了热传输机制的理论分析;最后讨论了减小封装热阻、提高热可靠性的方法。结果表明:适当提高塑封材料的热传导率、增加PCB面积和施加一定风速的强迫对流均可降低QFP48封装的热阻,提高散热效果。

Aim at the general QFP48lead frame package,the heat transfer mechanism was firstly discussed,and the theoretical computing results for the thermal resistance was provided;then,the QFP48finite element model was established by utilizing the Ansys Icepak software.The simulated results show good consistency with the theoretical analysis on the heat transfer mechanism.Finally,methods to reduce the thermal resistance and to improve the thermal reliability were discussed.The simulation results show,by properly increasing the thermal conductivity of the molding compound,increasing the area of PCB and introducing a forced convection,that the thermal resistance of QFP48package is reduced and the heat dissipation effect is improved.