Study on the optical parameters and thin film’s thickness by polarization modulation spectroscopic ellipsometer

• Main Authors: Yu-Chung Huang, 黃毓中
• Other Authors: Jen-Bin Shi
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/tqbtef

碩士 === 逢甲大學 === 電子工程所 === 90 === The study of this paper focus on the need of the industry of semiconductor. The process of semiconductor is large amount of product, good yielding, high speed. It is necessary to develop a system of monitor on line. Ellipsometer use the character of the polarization of the light. As the incident light arrives at interface of the sample, the character of light will change.We will get the character of material,the index of refraction and the thickness of thin film, from the change of the polarization of light.The ellipsometer is more sensitive than other optical methods.The ellipsometer measures the thickness of the thin film by the change of the phase.We choice the ellipsometer by the reason. We will introduce PMSA（Polarizer-Modulation-Sample-Analyzer）ellipsometer. PMSA ellipsometer will measure the elliposmeter parameters, y（psi）and △（delta）.We use monochromator to modulate wavelength to prove the accuracy of the experiment. When the electric field which is parallel to the incident field is the same as it which is perpendicular to the incident field（the azmuth of the polarizer is 45 degree to the incident field）,we use the retardation of the PEM（photoelastic modulation）to modulate the change of the polarization.（palarization of circular,elliptical,and linear）.We will get the optical signal from detector and we use SCU（The Signal Condition Unit）to derive the broadband AC for the input to a lock-in amplifier（I1f、I2f） and DC signals（Idc）.for calculating the ratio AC/DC .We can use Idc、I1f and I2f to derive y（psi）and △（delta）.We use y（psi）and △（delta）to derive the index of refraction（n、k）.When we derive the index of refraction of thin film and the thickness of thin film,we have to use “the simplex”.