Optical measurement system using polarized light
First Claim
1. An optical measurement system for evaluating a substrate, the system comprising:
- an intensity stabilized light source configured to generate a stabilized light beam,a polarizing element for polarizing the light beam emanating from the light source to provide a polarized light beam,an optical system for directing the polarized light beam to a particular location on the substrate,a controllable translatable assembly for moving the polarized light beam across at least a portion of the substrate such that the polarized light beam impinges upon multiple locations on the substrate,a position indicating means for determining the particular location on the substrate upon which the polarized light beam impinges,a detection system configured to evaluate light reflected from the particular locations on the substrate upon which the polarized light beam impinges, the detection system includinga polarization analyzing element for separating the light from the particular locations on the substrate into s-polarized light and p-polarized light,a first optical sensor measuring amplitude of the s-polarized light,a second optical sensor measuring amplitude of the p-polarized light, anda third optical sensor measuring reflection angle of the reflected light relative to the substrate, anda control system for compiling a data set correlating the measured amplitude of the s-polarized light, the p-polarized light, and the measured reflection angle with the particular location on the substrate upon which the polarized light beam impinges for determining changes in the substrate.
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Accused Products
Abstract
An optical measurement system for evaluating the surface of a substrate or the thickness and optical characteristics of a thin film layer overlying the substrate includes an intensity stabilized light source configured to generate a stabilized light beam, a polarizing element for polarizing the light beam emanating from the light source, and a detection system for measuring the light reflected from the substrate The measurement system includes a polarizing beam-splitter for splitting the light reflected from the substrate into s-polarized light and p-polarized light. The measurement system further includes two optical sensors for separately measuring the amplitude of the s-polarized light and the intensity of the p-polarized light and a third detector for measuring either the phase difference between the s-polarized light and the p-polarized light or the reflection angle of the light reflected from the substrate. A control system analyzes the measured amplitude of the s-polarized light and the p-polarized and either the phase-difference or the reflection angle to determine changes in the topography of substrate or changes in the thickness or optical characteristics of the thin film layer.
128 Citations
15 Claims
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1. An optical measurement system for evaluating a substrate, the system comprising:
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an intensity stabilized light source configured to generate a stabilized light beam, a polarizing element for polarizing the light beam emanating from the light source to provide a polarized light beam, an optical system for directing the polarized light beam to a particular location on the substrate, a controllable translatable assembly for moving the polarized light beam across at least a portion of the substrate such that the polarized light beam impinges upon multiple locations on the substrate, a position indicating means for determining the particular location on the substrate upon which the polarized light beam impinges, a detection system configured to evaluate light reflected from the particular locations on the substrate upon which the polarized light beam impinges, the detection system including a polarization analyzing element for separating the light from the particular locations on the substrate into s-polarized light and p-polarized light, a first optical sensor measuring amplitude of the s-polarized light, a second optical sensor measuring amplitude of the p-polarized light, and a third optical sensor measuring reflection angle of the reflected light relative to the substrate, and a control system for compiling a data set correlating the measured amplitude of the s-polarized light, the p-polarized light, and the measured reflection angle with the particular location on the substrate upon which the polarized light beam impinges for determining changes in the substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of evaluating a substrate comprising the steps of generating an intensity stabilized light beam;
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polarizing the light beam to form a polarized light beam, directing the polarized light beam to a particular location on the substrate, separating the polarized light beam after reflection from the particular location on the substrate into two orthogonally polarized light beams, measuring the amplitude of each of the orthogonally polarized light beams, measuring the reflection angle of the reflected light relative to the substrate, and analyzing the measured amplitude of each of the two orthogonally polarized light beams and the measured reflection angle of reflected light beam to determine changes in the substrate. - View Dependent Claims (13, 14, 15)
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Specification