塑封SiC功率器件在高温损耗功率下的热应力和断裂分析  

Thermal Stress and Fracture Analysis of Plastic Encapsulated SiC Power Devices Under High Temperature Power Dissipation

作　　者：傅朝 王珺[1] Fu Zhao;Wang Jun(Department of Materials Science,Fudan University,Shanghai 200433,China)

机构地区：[1]复旦大学材料科学系,上海200433

出　　处：《半导体技术》2025年第4期393-398,共6页Semiconductor Technology

基　　金：国家自然科学基金(61774044);教育部创新平台专项。

摘　　要：塑封SiC功率器件是新能源汽车电力电子技术的核心,其在高温环境、高功率下工作的可靠性是关键问题。对具有顶部散热结构的塑封SiC功率器件,考虑高温环境下芯片的损耗功率,利用有限元分析(FEA)研究了热应力分布,并采用虚拟裂纹闭合技术(VCCT)分析了塑封器件的界面断裂问题。结果表明,塑封器件热应力集中在芯片和焊料层界面,较薄的芯片和适当增厚的焊料层可有效降低界面的断裂风险;当预裂纹长度超过100μm时,芯片和焊料层界面裂纹可能扩展;裂纹前缘更易形成弧形;裂纹扩展与张开、剪切和撕裂三种断裂模式相关,对面外相位角分析发现撕裂模式在裂纹边角处占比更高,而裂纹中间区域以剪切模式为主。Plastic encapsulated SiC power devices is the core of power electronics technology for new energy vehicles,and their reliability is a key issue for the operation of the devices under high-temperature environment and high power.For three-dimensional plastic encapsulated SiC power devices with a top heat dissipation structure,the distribution of thermal stress was investigated by using finite element analysis,considering the chip power dissipation in high-temperature environment.The interfacial fractures of the plastic encapsulated devices were analyzed using the virtual crack closure technique(VCCT).The results indicate that thermal stress of the plastic encapsulated device is concentrated at the interface between the chip and the solder layer,and thinner chips and solder layer of appropriate thickness can effectively mitigate the risk of fracture at the interface.When the pre-crack length exceeds 100μm,the crack at the interface between the chip and the solder layer may expand,and the leading edge of the crack is more easily to form curved fronts.The crack expansion is related to three fracture modes,namely,tension,shear and tearing.The tearing mode is found to be more predominant at the edges and corners of the crack through the out-of-plane phase angle analysis,while the shear mode dominates in the middle region of the crack.

关 键 词：SIC 断裂 热应力 极端工况 有限元分析(FEA) 虚拟裂纹闭合技术(VCCT) 

分 类 号：TN43[电子电信—微电子学与固体电子学] TN406