SOI CMOS电路稳态寿命试验后漏电失效分析

针对SOI COMS电路稳态寿命试验后输入漏电流超标开展失效分析，分别对异常掉电致击穿、离子沾污、内部气氛不佳、芯片外表面污染、静电放电（ESD）等因素进行排查分析。定位电路失效原因为ESD防护用具状态不佳，导致试验过程中产生的ESD使电路输入端口二极管发生栅氧击穿。通过ESD测试设备模拟和原试验过程模拟2种方式，对失效模式进行复现验证。结果表明:SOI CMOS电路在试验过程中，即使试验员按要求佩戴防静电腕带和绝缘指套，若防静电腕带或绝缘指套状态不佳，仍易引发样品ESD失效；失效模式通常为电路输入端口微安级漏电，且该漏电在高温退火后会有部分恢复。建议在试验过程中选用全金属防静电腕带和防静电专用指套；若选用尼龙编制腕带，须定期更换。

Failure Analysis of SOI CMOS Circuit After Steady-state Life Test

The failure analysis of the input leakage of the SOI COMS circuit after steady-state life test was carried out. The possible failure causes such as breakdown caused by abnormal power off, ion contamination, abnormal internal atmosphere, external surface pollution of chip and Electro-Static discharge (ESD) were investigated and analyzed. The failure cause of the circuit was identified as that ESD protective equipment was not in good condition, which led to breakdown of the diode at the input port of circuits caused by ESD generated during the test. The failure mode was repeated and verified by ESD test equipment simulation and original test process simulation. In the test process of SOI CMOS circuit, even if the tester wears an antistatic wrist strap and finger-cots as required, it is also easy to cause ESD failure of samples while the working status of corresponding equipment is poor. The failure mode is usually microampere leakage at the input port of the circuit, which will be partially recovered after high temperature annealing. It is recommended to select metal antistatic wrist straps and special antistatic finger-cots during the test. If nylon wrist straps are selected, it must be replaced regularly.