Spectral ellipsometer based on Faraday effect and measurement method

Abstract

The invention discloses a spectral ellipsometer based on a Faraday effect and a measurement method, the ellipsometer comprises a light source, a first polarizer, a sample stage, an optical rotation module, a second polarizer and a detector, and the light source, the first polarizer, the sample stage, the second polarizer and the detector are sequentially arranged along a light propagation path; the optical rotation module comprises a columnar plano mirror and an electromagnetic coil, the columnar plano mirror is located in the center of the interior of the electromagnetic coil, the central axis of the columnar plano mirror, the optical axis of reflected light of a to-be-detected sample and the magnetic field direction of the electromagnetic coil are consistent, and the electromagnetic coil is connected with a direct-current power supply; and the measurement method is based on the ellipsometer. The ellipsometer is simple in structure, does not comprise a mechanical motion part, is simple in control logic, is high in measurement precision, and is high in speed.

Description

technical field [0001] The invention belongs to the field of spectroscopic ellipsometers, in particular to a spectroscopic ellipsometer and a measuring method based on the Faraday effect. Background technique [0002] Ellipsometer is mainly used for non-destructive measurement of film thickness of various materials. The Spectroscopic Ellipsometer is more capable of obtaining measurement results for a wide range of spectra at the same time, so the measurement range is wider and the accuracy is higher. One of the existing (broad) spectral ellipsometers is a rotating device type, which uses a mechanical rotating polarizer to obtain the ellipsometric light spectrum data reflected by the sample; the other is to use a photoelastic modulator to obtain the same data . However, there are deficiencies in these two methods. The control process of the first method is relatively mature and the cost is low, but due to the existence of mechanical movement, the accuracy of control and dat...

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Problems solved by technology

However, there are deficiencies in these two methods. The control process of the first method is relatively mature and the cost is low, but due to the existence of mechanical movement, the accuracy of control and data acquisition is poor, and the measurement speed is relatively slow; especially the mechanical movement The existence of components makes it difficult for current ellipsometers to be directly installed in high-vacuum chambers, making it impossible to better monitor certain modern high-precision manufacturing processes; the second type of photoelastic device is expensive and has strict requirements on the working environment , it is more difficult to control

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