28 nm技术节点微小多晶硅桥连缺陷检测与改进方法的研究

Tiny Poly Bridge Defects Detection and Reduction for 28 nm Technology Semiconductor Manufacturing Engineering

针对28 nm技术节点产品上多晶硅微小桥连缺陷,应用电压衬度与光学检测系统,探索了缺陷检测方法的开发流程,建立了缺陷监控指标,并据此评估了缺陷的改善方案。对缺陷检测方法开发流程进行了创新:通过电压衬度系统进行精确扫描,检测出的微小桥连缺陷经电子束表面标记,被用于光学检测系统进行扫描条件开发,最终确定的光学扫描方法被用于缺陷监控与缺陷改善。根据实验结果,进一步推论了缺陷形成的机理,优化了光刻与干刻工艺条件,更换了全新类型的光阻材料,从而使缺陷问题得到解决。电子束扫描所提供的电压衬度像为扫描程式的开发提供了较高的分辨率,弥补了亮场缺陷检测方法分辨率较低的局限。缺陷在线监控指标的建立为在线工艺改善提供了在线数据指标,与良率测试结果相比,加快了先进制程产品的研发进度。

Detection and reduction method of tiny poly bridge defects for 28nm technology semiconductor was studied.With optical and electron-beam inspection systems,random-distributed tiny poly line-end bridge defects in SRAM were explored and investigated.Then the difficulty of localizing defects in SRAM was overcome.Meanwhile,inline detection method and index of the defect was studied and setup.Subsequently,the failure model of the defect was established and the effective defect reduction actions were carried out.Instead of end of line(EoL)electrical test,the process changes could be inline verified by proposed detection and monitoring methods,and which achieved a tremendous saving in time,speeded up the technology development and made the production available for mass manufacturing.