Characterization of Interfacial Layer of DUV Coatings by Spectroscopic Ellipsometry

Abstract

The Interfacial layer has an important influence on the optical performance of the deep ultraviolet (DUV) coatings. The variable angle Spectroscopic ellipsometry measurements of three kinds of DUV coating samples were performed in the wavelength range 150-500nm using a purged variable angle Spectroscopic ellipsometer. The samples include the single layer sample, double layers sample, and three layers sample. The thickness and optical index of the MgF2 layer and LaF3 layer as well as those of the interfacial layer between them were obtained by successful regression of the SE measurements. For the single layer, the agreement of the results between the SE and the spectrophotometic techniques was very good. The obtained thickness of the two kinds of interfacial layer was in consistent with the RMS results of the single layer obtained by AFM, indicating the obtained results were reliable.