功率模块封装键合线的通流能力:模型与实证

Ampacity of Bonding Wire for Power Module Packaging:Model and Experiment

与Si芯片相比,SiC芯片具有更高的电流密度、结-壳热阻和工作结温,以及更少的芯片面积、键合面积和并联键合线,导致键合线的电-热应力急剧增加,对SiC功率模块的安全可靠运行,面临着严峻挑战,因此急需掌握功率模块封装键合线的通流能力极限。从电流密度和工作结温两方面,该文厘清SiC功率模块封装键合线的技术问题,基于键合线的电-热耦合模型,计及持续电流和脉冲电流的运行工况,考虑单根键合线和多根键合线并联的影响,建立定量描述键合线通流能力的数学模型,针对多种常用直径的键合线,采用大量的仿真和实验对比研究,验证了模型及其方法的有效性和正确性,发现并联键合线的电流退额效应,为SiC功率模块的封装键合线设计,提供基础理论和技术方法指导。

Compared with the Si counterpart,the SiC power device performs higher current density,junction-case thermal resistance and junction temperature,smaller footprint size,active bonding area and parallel bonding wires.Therefore,the electro-thermal stress of the bonding wire increases dramatically,which challenges the safety and reliability of the SiC power module.The ampacity of bonding wire of the next-generation power packaging is urgently pursued.From the aspects of current density and junction temperature,the obstacles of bonding wire for SiC power module packaging are clarified.Taking the continuous or pulsed load current into account,insightful mathematical models are established to characterize the ampacity of single and parallel bonding wires.By using bonding wires with different diameters,the simulated and experimental results are presented to ensure the effectiveness and validation of the proposed models.The ampacity degradation effect of parallel bonding wires is modeled and examined.This paper can provide guidance for the optimal design of bonding wire for the SiC power module.