28 nm锗硅工艺极微小颗粒缺陷监控方法与改善措施研究

Investigation of SiGe Extreme Tiny Defects Detection and Reduction for 28nm Technology

针对28 nm产品锗硅工艺产生的极微小颗粒缺陷,应用光学检测系统,探索了缺陷检测方法,建立缺陷的在线监控指标。据此建立缺陷失效模型和评估了缺陷的改善方案。对缺陷检测方法进行了系统的研究:通过热扫描检出缺陷样本,收集并分析缺陷样本在不同扫描条件组合下的信号噪声比,最终确定缺陷检测条件。根据工艺特性以及相关试验结果建立了缺陷失效模型,据此推导缺陷改善方向,并最终通过实验验证了改善措施的有效性。最终通过优化锗硅工艺前湿法清洗、优化锗硅工艺前氧化硅薄膜质量以及优化锗硅工艺选择比等条件,使缺陷问题得到解决。针对极微小颗粒缺陷的系统性研究,最终建立了有效的缺陷在线监控指标,为缺陷改善带来了便利,加快了先进制程的研发进度。

Detecti on and reduction methods of SiGe extreme tiny defects for 28 nm tech no logy semic on ductor were studied.The extreme tiny defects detecti on method was systematically studied and the effective defects detection recipe was fixed.Then the defects failure model was proposed and the defects reduction methods were elicited.Subsequently,the effective defects reduction actions,including optimizing the processes of SiGe pre clean,quality of SiGe hard mask oxide film and selectivity of SiGe epitaxy,were carried out.Instead of end of line(EoL)electrical test,the processes change could be inline verified by proposed detecti on method.Furthermore,the method speeded up the tech no logy development.