【摘要】 针对BCD工艺中出现的NMOS管结漏电问题进行研究,通过失效分析的方法发现有结穿刺现象,怀疑为金属阻挡层工艺窗口较小。为进一步调查金属阻挡层的工艺容宽,尝试采用了苛刻的多次合金的方法对当前使用的阻挡层进行考察,发现经过多次合金处理的产品成品率大幅下降,从而确认金属阻挡层的工艺容宽较小。为了改进工艺进行准直溅射阻挡层、不同的金属阻挡层厚度、RTP、小应力阻挡层等试验,并结合多次合金的方法对阻挡层进行了考核。实验结果表明,应力过大是NMOS管漏电的根本原因。最后研发出一种优化的小应力阻挡层菜单,并成功应用于BCD工艺量产中。更多还原

【Abstract】 In this work,we studied the NMOS junction leakage issue in BCD process.The junction spiking was observed by failure analysis.The barrier layer was suspected marginal.To further investigate the barrier robustness,we tried critical multiple-alloy on present barriers and found the yield from the multiple-alloy group was reduced sharply.This confirmed our suspicions.Barrier layers thickness,collimator barrier and new barrier with smaller stress were tried for barrier optimization.No yield loss was observed from the stress improved barrier after critical several times alloy.The root cause of NMOS leakage was high stress from the barrier layer.The robust barrier was developed with small stress.Finally it was successfully used in BCD process ramping up.更多还原