高压IGBT封装硅凝胶材料高温和热老化绝缘特性研究

Research on high temperature and thermal ageing insulation properties of silicone gel material for high voltage IGBT packaging

在高压IGBT器件中,新兴的宽禁带半导体芯片逐渐代替了传统的硅基半导体芯片,其高功率密度特性会导致电力电子模块的工作温度急剧上升。硅凝胶作为高压IGBT器件的封装用绝缘材料,其绝缘性能面临高温和热老化的挑战。为了研究高温和热老化对硅凝胶材料热稳定性和绝缘性能的影响,本文基于硅凝胶材料的高温试验与热老化试验,测试了高温和长期热应力作用对硅凝胶材料介电性能、体积电导率和击穿强度的影响,对硅凝胶的高温特性和热老化特性进行分析。结果表明:随着温度的升高,硅凝胶的复介电常数实部降低、介质损耗增加、直流电导率升高、击穿强度降低;随着热老化时间的增加,硅凝胶的复介电常数实部增加、介质损耗先减小后增大、直流电导率先增大后减小、击穿强度降低。

In high-voltage insulated gate bipolar transistor(IGBT) devices,traditional Si-based semiconductor chips are gradually replaced by emerging wide-bandgap semiconductor chips.High-power-density wide-bandgap semiconductors lead to a sharp rise of operating temperature in power electronic modules.Silicone gel is used as an insulating material for the packaging of high-voltage IGBT devices,and its insulating performance faces the challenges of high temperature and thermal ageing.In order to study the effects of high temperature and thermal ageing on the thermal stability and insulating properties of silicone gel,we studied the effects of high temperature and long-term thermal stress on the dielectric properties,volume conductivity,and breakdown strength of silicone gel by high temperature experiments and thermal ageing experiments of silicone gel materials,and analyzed the high temperature characteristics and thermal ageing characteristics of the silicone gel.The results show that with the increase of temperature,the real part of complex permittivity and breakdown strength of silicone gel decreases,and the dielectric loss and DC conductivity increases.With the increase of thermal ageing time,the real part of complex permittivity of silicone gel increases,the dielectric loss decreases at first and then increases,the DC conductivity increases at first and then decreases,and the breakdown strength decreases.