Abstract
The semiconductor industry has applied different metrologies to optimize the manufacturing process and maintain certain quality of the final products. There are many tools used to control Critical Dimension (CD) of integrated circuits during each manufacturing process such as CD Scanning Electron Microscopy (CD-SEM), CD Atomic Force Microscopy (CD-AFM) and CD Small Angle X-ray Scattering (CD-SAXS). However, those tools are either time-consuming or sample-damaging. In this thesis, we have developed a new type of scatterometer to reconstruct surface structures of one-dimensional gratings by measuring diffraction signals. We applied a High-Harmonic Generation (HHG) Extreme-Ultraviolet (EUV) light source with wavelengths ranging from 25 nm to 34 nm in our research. The current results reveal satisfactory reconstruction of the grating structures which included densities of 1200 lines/mm and 7200 lines/mm. Additionally, we have developed a data-matching technique using Rigorous-Coupled Wave Analysis (RCWA) for our EUV scatterometers. The data matching method has given results of depths, top CDs and bottom CDs with discrepancies all smaller than 5 percent after comparing to SEM images. Finally, an analytical method has been presented in order to evaluate the performance of our scatterometers and guidelines of designing EUV scatterometers are also discussed from different viewpoints at the end.