Title :
DUV Broadband Spectroscopic Ellipsometer Based on All-Reflective Focusing Optical System
Author :
Guozhi Song ; Yaqin Chen ; Tao Liu ; Gaozeng Cui ; Jiandong Wang
Author_Institution :
Key Lab. of Microelectron. Devices & Integrated Technol., Univ. of Electron. Sci. & Technol. of China, Chengdu, China
Abstract :
Ellipsometer is a powerful tool to determine the thickness and optical properties of thin films. Usually, traditional spectroscopic ellipsometer employing Tran missive lenses for beam collimation and focusing are only accurate over a limited spectral range due to high chromatic aberration and low transmittance. In this paper, we describe a ellipsometer that uses all-reflective focusing optical components to extend the wavelength range from Deep-UV 200 nm to near-infrared 1000 nm and focuses the collimated beam into a small spot size (36×49μm). This focused beam spectroscopic ellipsometer includes four off-axis parabolic mirrors and two flat mirrors, in which flat mirrors are used to change the propagation direction and compensate the polarization changes caused by off-axis parabolic mirrors to obliquely focus on the sample surface. By careful construction, alignment, and calibration of the rotating-compensator ellipsometer, we measured the thickness of SiO2 thin film on Si substrate with a maximum absolute error of 2.15 Å in the thickness range of 30 to 130 Å.
Keywords :
aberrations; calibration; compensation; ellipsometers; lenses; light reflection; mirrors; optical collimators; optical constants; optical focusing; thickness measurement; thin films; ultraviolet spectroscopy; DUV broadband spectroscopic ellipsometer; all-reflective focusing optical system; beam collimation; chromatic aberration; flat mirrors; off-axis parabolic mirrors; optical property determination; polarization change compensation; rotating compensator ellipsometer calibration; thickness measurement; thin films; transmissive lenses; wavelength 200 nm to 1000 nm; Broadband communication; Calibration; Ellipsometry; Focusing; Mirrors; Optical polarization; focused-beam ellipsometry; off-axis parabolic mirrors; polarization; spectroscopy;
Conference_Titel :
Instrumentation, Measurement, Computer, Communication and Control (IMCCC), 2013 Third International Conference on
Conference_Location :
Shenyang
DOI :
10.1109/IMCCC.2013.112