Advanced TEM sample preparation and imaging techniques in semiconductor devices

In this paper, we present three cases studies with dedicated FIB-TEM technique that developed to characterize each of them. The first case describes a FIB sample preparation method that can include two columns of the structure of interest into one sample. It is a useful technique to characterize the overlay offset when more than one column of the structures is concerned. The second case is about to prepare an ultra-thin TEM sample which minimizes the shadowing effect and nano-roughness in localized area. Such thin samples are ideal for high resolution imaging and crystal structure analysis. In the last case, one TEM imaging technique is developed to enhance the defect contrast by utilizing the Fresnel fringes when there is not enough contrast can be obtained from normal in focus imaging condition. Theoretical description of the Fresnel fringes is also provided to illustrate the origin of extra contrast that can obtain from this technique.