Reflection-type near-field optical polarization spectrometer

Abstract

The invention relates to a reflection-type near-field optical polarization spectrometer. The spectrometer comprises an incident light generation module, a probe scanning microscopic module and an emergent light detection module; detection light is shaped and modulated in the incident light generation module, so that detection light in different polarization states is emitted; an incident light beam is focused on a probe tip of the probe scanning microscopic module; the detection light interacts with a micro-nano space structure formed by the probe tip and the surface of a sample, the polarization state of the detection light changes, and then the reflected light / scattered light of the light beam is collected by the emergent light detection module and then is shaped and focused. According to the reflection-type near-field optical polarization spectrometer of the invention, nanoscale ultrahigh transverse spatial resolution can be realized, and the requirement of a semiconductor key device for nanoscale size accurate measurement is met; the defocusing problem caused by chromatic aberration generated by using a lens element can be avoided; a polarization-maintaining structure can ensure that the polarization state of the modulated detection light is kept unchanged when the modulated detection light reaches a probe after being reflected by a reflecting element; and the spectrometer has the advantages of no contact with the sample, no damage to the sample and the like.

Description

technical field [0001] The invention relates to the technical field of spectrometer testing, in particular to a reflective near-field optical polarization spectrometer. Background technique [0002] With the development of semiconductor manufacturing technology, the critical dimensions of semiconductor devices are continuously shrinking, and the 5nm node has been realized. At the same time, the semiconductor manufacturing industry has higher and higher requirements for lateral spatial resolution of device size measurement. The parameters measured by the traditional polarization spectrometer are the average value of the probe light in the spot formed on the surface of the sample to be tested. Although the vertical resolution of traditional polarimeters depends on the phase measurement sensitivity of the instrument, and generally can achieve Angstrom level, the lateral resolution of polarimeters is limited by the spot size, and the spot size diameter of micro-spot type polarim...

AI Technical Summary

Problems solved by technology

[0003] When the light source in the polarized spectrometer uses a wide-spectrum light source, the use of lens elements in the polarized spectrometer to shape and focus the probe beam will cause different wavelengths of light to focus at different positions due to chromatic aberration. In this case, the wide-spectrum beam is focused to Inaccurate measurements due to dispersion at the tip of the stylus; even with an achromat, it is difficult to get good results across the entire spectrum

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