Optical measurement system with simultaneous multiple wavelengths, multiple angles of incidence and angles of azimuth

Abstract

The present invention discloses an optical measurement and / or inspection device that, in one application, may be used for inspection of semiconductor devices. It comprises a light source for providing light rays; a half-parabolic-shaped reflector having an inner reflecting surface, where the reflector having a focal point and an axis of summary, and a device-under-test is disposed thereabout the focal point. The light rays coming into the reflector that is in-parallel with the axis of summary would be directed to the focal point and reflect off said device-under-test and generate information indicative of said device-under-test, and then the reflected light rays exit said reflector. A detector array receives the exited light rays and the light rays can be analyzed to determine the characteristics of the device-under-test.

Description

[0001] priority claim [0002] This patent application claims U.S. Provisional Patent Application No. 60 / 799,043, "An Optical Measurement System with Simultaneous Multiple Wavelengths, Multiple Angles of Incidence and Angles of Azimuth") priority. This application is hereby incorporated by reference in its entirety. This patent application is also a continuation-in-part of US Nonprovisional Patent Application "Optical Focusing Device" filed on April 16, 2007 with application number 11 / 735,979. technical field [0003] The present invention relates to a detection and measurement system, in particular to optical detection and measurement of, for example, semiconductor devices and / or wafers for Device Under Test (DUT for short). Background technique [0004] The information generated by the reflection of a pilot beam from a device under test (DUT) has several uses. The thickness of different coatings (single-layer coating or multi-layer coating) on ​​the wafer can be determ...

AI Technical Summary

Problems solved by technology

First, since the lens material absorbs the incident light in the ultraviolet band, it is difficult to extend the wavelength of the incident light to the ultraviolet band (for example, the wavelength is less than 400nm)

Second, due to chromatic aberration, it is difficult to work simultaneously with broadband light, such as wavelengths from 250nm to 1000nm

Third, when light passes through the lens, there is a problem of light being absorbed, and the light intensity will decrease as it passes through the lens

Design options are limited due to the limited number of design variables

For example, reflective objectives designed by Schwarzchild have limited numerical aperture NA, block the central beam, and cannot achieve a wide range of angles of incidence

Aspheric reflective surfaces are also widely used, but in most cases they are used in a very traditional way, where the axis of symmetry is perpendicular to the reflective surface and the range of angles of incidence is limited

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