Ellipsometer and Measurement Method Based on Large Numerical Aperture Objective Lens Integrated Dark Field Observation

Abstract

The invention belongs to the related technical field of optical measurement, and particularly discloses an ellipsometer based on the integration of a large numerical aperture objective lens and dark field observation and a measurement method. The ellipsometer comprises an objective lens, a tube lens, and an illumination light path module and a bright field light path module that are symmetricallyarranged about a central axis. The illumination light path module comprises a light source, a monochromator, optical fiber, a polarizing arm and a first reflector, and the bright field light path module comprises a second reflector, a polarization analyzing arm and a bright field detector. The method comprises the following steps of: selecting polarized light with specified wavelength and characteristics, sequentially passing the polarized light through the illumination light path module to realize inclined incidence conditions of polarization measurement, then introducing a reflector and a vertical objective lens light path, and passing the light through the bright field light path module and the dark field light path module to realize bright field and dark field observation measurement at the same time. According to the invention, full-view-field high-resolution, low-cost and non-destructive precise measurement of the optical constant of a nano-structure film and the geometrical parameters like film thickness, nano-structure characteristic line width, line height, side wall angle and the like can be realized.

Description

technical field [0001] The invention belongs to the technical field related to optical measurement, and more specifically relates to an ellipsometer based on a large numerical aperture objective lens integrated dark field observation and a measurement method. Background technique [0002] Among the currently commonly used micro-nano measuring instruments, scanning tunneling microscope (STM) and atomic force microscope (AFM) use ultra-micro probes to scan the surface of the sample; scanning electron microscope (SEM) uses electron beams to hit the sample, The entire measurement process needs to be carried out in a vacuum environment. Although these instruments have high measurement accuracy and resolution, the measurement process is time-consuming and destructive, requiring separate sample preparation and high cost. In contrast, optical non-destructive testing usually has the advantage of low cost, and methods like interferometry and ellipsometry are fast, non-contact, and no...

AI Technical Summary

Problems solved by technology

However, such an optical path is limited by the object-image relationship and the depth of field of the objective lens under oblique incidence conditions. During the imaging process, the clear field of view will be limited to a narrow band-shaped area, which limits the scope of use of the device to a certain extent.

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