Characterizing optical constants of thin films for vacuum ultraviolet lithography applications
Journal
Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Journal Volume
43
Journal Issue
6 B
Pages
3684-3688
Date Issued
2004
Author(s)
Abstract
The determination of optical constants of thin films is an important requirement for the study of masks, antireflective coatings, and resist materials used in the vacuum ultraviolet (VUV) lithography process. We demonstrate a simple method for determining optical constants by measuring the reflectance of thin films with different incidence angles. In order to obtain accurate optical constants, the measurement of reflectance, incidence angles and thickness should be confirmed carefully. In addition, thickness measurements are not important for thick high-absorption films. The measured reflectance should be modified by the surface roughness of thin films particularly in vacuum ultraviolet regimes. The optical constants of various materials were obtained experimentally by this method without using complicated mathematics models.
Type
conference paper