Development and characterization of nano film thickness standards

Film thickness is an important geometric parameter in semiconductor technology, and the accuracy of its magnitude affects directly the overall performance of the device. In order to accurately control and characterize the film thickness parameters, a set of 2nm~1000nm SiO₂ film thickness standards were developed to carry out measurement technology research. Firstly, a method of growing SiO₂ on pure Si wafer by a thermal oxidation process was used to develop a standard sample of the film thickness, and to evaluate the uniformity and stability. Secondly, the measurement model and method were studied, and the thickness of the film was characterized, based on the spectral ellipsometer. Finally, the uncertainty of measurement results to the standard are evaluated, based on the MCM simulation method. The results show that the uniformity of film thickness is better than 0.3nm, the stability is better than 0.2nm, and the uncertainty is 0.4nm~1.4nm, k=2.