The research of 28nm NMOS TEM sample junction stain analysis

Ion implantation is the most important silicon doping method in the process of semiconductor manufacturing. The common used analysis methodology such as FIB/SEM/TEM is restricted in analyzing the ion implantation related defects, while the chemical stain technology can provide very essential data in ion implantation process. The etching mechanism of silicon is very complicated with the mixture of HNO₃/HF/CH₃COOH. The influence factors of the etching by acid include the acid component ratio, the acid temperature, the buffer agent and so on. This article studies the influence factors of solution composition ratio and chemical reaction temperature in etching rate of silicon. By optimizing the mixture proportion and chemical reaction condition, it can define the low etching rate acid mixture for semiconductor device structure. This method has been successfully used in N type doped junction stain analysis technology of 28nm TEM sample.