电压衬度方法检测先进制程中极微小物理缺陷的研究

Study on Extreme Tiny Physical Defects Detection in Advance Process by Electron Beam Inspection

针对STI表面极微小氧化物残留缺陷,探索了应用电压衬度检测缺陷的方法,建立了缺陷监控指标,并据此评估了缺陷的改善方案。对缺陷检测方法进行了机理分析:通过调整电荷的积累与释放速率,增强缺陷的形貌衬度信号。根据实验结果,进一步推论了缺陷形成的机理,优化了化学机械研磨工艺条件并更新了研磨液种类,从而使缺陷问题得到解决。E-beam扫描提供的全新检测方法,弥补了亮场缺陷检测方法分辨率较低的局限,为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。

Focusing on extreme tiny oxide residue defects,the effective defect detection method with electron beam(E-beam)inspection tool was studied,the defects in line index was setup,and defects’reduction actions were evaluated with the index.Then the theory of the defects detection method was analysed,and balancing the charging rate and discharging rate of wafer surface was found as the key factor of sensitivity tuning.According to the results of a series of experiments,the mechanism of the extreme tiny oxide residue defects was exposed,and the defects reduction actions,including optimization of chemical and mechanical polishing(CMP)process and application of new type slurry,were implemented.Then the extreme tiny oxide residue defects trend low.Voltage contrast(VC)inspection with E-beam inspection tool supplied the higher resolution than bright field inspection tool.Furthermore,comparing with the end of line final test result,the inline index speeded up the progress of the 28nm technology production.