Analysis of multilayer structure for reflection of extreme-ultraviolet wavelength

Abstract

Mo/Si multilayers deposited by sputtering for application to extreme-ultraviolet (EUV) reflectors have been characterized. Si rice the control of d-spacing is critical for achieving higher reflectivity. an effective and accurate d-spacing measurement technology is required. Although cross-sectional transmission electron microscope (TEM) and low-angle X-ray diffraction (XRD) are standard methods for evaluating multilayers. they provide different d-spacing values front each other. Cross-sectional TIN images can allow direct measurement of individual layers and cannot reveal tire optical behavior of the multilayer. On the other hand, low-angle XRD analysis can provide the resultant d-spacing which includes nonideal factors. As a result look-angle XRD can predict the EUV peak position more precisely than TEM analysis.