DC/DC电源模块可靠性的研究

Reliability of DC/DC Power Supply Module

对当前较广泛应用的DC/DC电源模块这一多芯片组件(MCM)的可靠性进行了研究.通过对模块使用可靠性的统计,利用ANSYS软件对模块表面温度分布的模拟得出影响其可靠性的关键器件为垂直双扩散金属-氧化物-半导体场效应晶体管(VDMOS)和肖特基势垒二极管(SBD).使用以器件参数退化为基础的恒定电应力、序进温度应力加速寿命试验方法分别获得VDMOS和SBD的失效敏感参数为VDMOS的跨导gm和SBD的反向漏电流IR;VDMOS和SBD的平均寿命分别为1.47×107h和4.3×107h.分析表明,这2种器件参数的退化均与器件的Na+沾污和Si-SiO2界面的退化有关,同时SBD的参数退化还与Al-Si界面的退化有关.

The reliability of DC /DC power supply module-multichip module was investigated.By statistics the failure of modules applied and analysis the temperature distribution of the module used ANSYS software,it has found that the key devices affecting the reliability are VDMOS and SBD in the module.Then the VDMOS and SBD were tested under constant electrical stress and progressive temperature stress based on the parameter degradation.It concludes that the failure sensitive parameter are transconductance gm for VDMOS and reverse current IR for SBD,the average life span of VDMOS and SBD are 1.47 × 107 hours and 4.3 × 107 houres respectively from the extrapolation of accelerated life test curve.In conclusion,the degradation of VDMOS and SBD is dependent on the Na ＋ contamination and Si-SiO2 interface degradation.At same time,the degradation of SBD is also dependent on Al-Si interface degradation.