KR-20260064347-A - A single optical element rotational ellipsometer

KR20260064347AKR 20260064347 AKR20260064347 AKR 20260064347AKR-20260064347-A

Abstract

The present invention provides a single optical element rotary ellipsometer characterized by comprising: a light source unit that irradiates incident light toward at least a portion of a sample; a first polarizing unit disposed between the sample and the light source unit to linearly polarize the incident light; a second polarizing unit disposed between the first polarizing unit and the sample to rotationally polarize the incident light linearly polarized by the first polarizing unit; a polarization detector unit that polarizes measurement light reflected or transmitted from the sample at a plurality of angles and measures the optical characteristics of the measurement light polarized at a plurality of angles; a calculation unit that calculates Muller matrix components of the sample from the light quantity values measured by the polarization detector unit; and a control unit that controls the first polarizing unit and the second polarizing unit to selectively perform a light quantity control mode for controlling the light quantity of the measurement light and simultaneously selectively perform a polarization measurement mode.

Inventors

조용재
제갈원

Assignees

한국표준과학연구원

Dates

Publication Date: 20260507
Application Date: 20241031

Claims (12)

A light source unit that irradiates incident light toward at least some of the samples; A first polarizing unit disposed between the sample and the light source unit to linearly polarize the incident light; A second polarizing unit disposed between the first polarizing unit and the sample to rotate polarize incident light linearly polarized by the first polarizing unit; A polarization detection unit that polarizes the measurement light reflected or transmitted from the above sample at multiple angles and then measures the optical characteristics of the measurement light polarized at multiple angles; A calculation unit that calculates the Muller matrix components of the sample from the light quantity value measured by the polarization detection unit; and A single optical element rotary ellipsometer characterized by including: a control unit that controls the first polarization unit and the second polarization unit to selectively perform a light intensity control mode for controlling the light intensity of the measurement light and simultaneously selectively perform a polarization measurement mode.
A light source unit that irradiates incident light toward at least some of the samples; A first polarizing unit disposed between the sample and the light source unit to linearly polarize the incident light; A second polarizing unit positioned adjacent to the sample and rotatingly polarizing the measurement light that is reflected or transmitted after the incident light linearly polarized by the first polarizing unit is irradiated onto the sample; A polarization detection unit disposed adjacent to the second polarization unit, which polarizes the measurement light rotated polarized by the second polarization unit into multiple angles and then measures the optical characteristics of the measurement light polarized into multiple angles; A calculation unit that calculates the Muller matrix components of the sample from the light quantity value measured by the polarization detection unit; and A single optical element rotary ellipsometer characterized by including: a control unit that controls the incident light converter and the measurement light analysis unit to selectively perform a light intensity control mode for controlling the light intensity of the measurement light and simultaneously selectively perform a polarization measurement mode.
In Article 1 or Article 2, A single optical element rotating ellipsometer characterized in that the first polarizing unit comprises at least one first linear polarizer to control the amount of light and make the measurement light into a linearly polarized state.
In Article 1 or Article 2, A single optical element rotary ellipsometer characterized in that the second polarizing part is either a second linear polarizer or a compensator.
In Article 1 or Article 2, A single-light element rotary ellipsometer characterized in that the light source is either a white light source that irradiates at least a portion of the samples with incident light having different wavelengths or a laser device that irradiates at least a portion of the samples with incident light having a single wavelength.
In Article 5, A single optical element rotary ellipsometer characterized by further including a color filter unit disposed between the light source unit and the polarization detector unit when the light source unit is the white light source, which converts the measurement light having different wavelengths into a monochromatic wavelength and directs it to the polarization detector unit.
In Article 5, The above polarization detector is, A polarization detection unit in which a plurality of unit polarization units are arranged in a matrix to polarize measurement light reflected or transmitted from the sample at a plurality of angles; and A detection member that measures the optical characteristics of a measurement light polarized at multiple angles by the above-mentioned polarization detection unit; The above polarization detection unit is positioned to face the sample, and A single optical element rotary ellipsometer characterized in that the detection member is disposed on the back surface of the polarization detection unit.
In Article 7, The above unit polarization unit is, A first unit polarization member having a plurality of first slit patterns formed at equal intervals perpendicular to the upper and lower surfaces of the detection member; A second unit polarizing member disposed on the other side of the first unit polarizing member, wherein a plurality of second slit patterns inclined at 45° with respect to the upper and lower surfaces of the detection member are formed at equal intervals; A third unit polarizing member disposed on the lower side of the first unit polarizing member, wherein a plurality of third slit patterns inclined at 135° with the upper and lower surfaces of the detection member are formed at equal intervals; and A single optical element rotary ellipsometer characterized by including: a fourth unit polarizing member disposed on the lower side of the second unit polarizing member, wherein a plurality of fourth slit patterns parallel to the lower surface of the detection member are formed at equal intervals.
In Article 7, A single optical element rotary ellipsometer characterized by further including an imaging optical system disposed between the sample and the detection member, which images by being equal to the area of the sample to which the measurement light is reflected, or by being enlarged or reduced compared to the area of the sample to which the measurement light is reflected.
In Article 1 or Article 2, A single optical element rotating ellipsometer characterized in that the above polarization measurement mode is a mode for measuring anisotropic optical properties of the sample at high speed.
In Article 1 or Article 2, The above detection unit further includes a light intensity sensor for measuring the amount of light of the measurement light, and When the amount of light measured by the light intensity sensor is included in a preset reference light intensity range, the control unit performs the polarization measurement mode, and A single optical element rotary ellipsometer characterized by the above-described control unit controlling the first polarizing unit to move to a first azimuth angle before measurement and to remain stationary during measurement in order to perform the polarization measurement mode, and controlling the second polarizing unit to rotate at a constant speed.
In Paragraph 3, A single optical element rotating ellipsometer characterized by the control unit adjusting the relative position of the characteristic axis of the linear polarizer with respect to the surface of the sample when there is one first linear polarizer, or adjusting the relative position between the azimuth angles with respect to the characteristic axis of the plurality of linear polarizers when there are multiple first linear polarizers, based on the amount of light measured by the light amount sensor when performing the light amount control mode.

Description

A single optical element rotational ellipsometer The present invention relates to a single optical element rotary ellipsometer, and more specifically, to a single optical element rotary ellipsometer that measures the Muller matrix components of a sample by selectively placing a second polarizer, which rotates at a constant speed by a control unit, between a first polarizer and a sample or between a sample and a polarization detector. In rapidly developing industrial fields related to semiconductor devices, flat panel displays, nanobiotechnology, nanoimprinting, and thin-film optics, the importance of technology capable of non-destructively and non-contactfully measuring and evaluating physical properties of nano-specimens, such as thin film thickness and nano-pattern shape, during the manufacturing process is steadily increasing. With the continuous development of the aforementioned industrial fields, the thickness of thin films has gradually decreased to the level of a few atomic layers, and the shape of nano-patterns is trending toward becoming more complex from the existing two-dimensional structure to a three-dimensional structure. The optical element-rotating ellipsometer resolves the residual polarization problem of the light source by making the light source linearly polarized through the addition of a stationary polarizer after the light source in the optical path of polarizer-rotating multichannel spectroscopic ellipsometers, and resolves the polarization dependency problem of the photodetector by transmitting linearly polarized light to the photodetector through the additional installation of a stationary polarizer before the multichannel spectrometer in the optical path of analyzer-rotating multichannel spectroscopic ellipsometers. However, although the optical element-rotating ellipsometer according to the conventional technology could determine the Fourier coefficients of the light intensity waveform, the ellipsometric angle of the specimen, and the unpolarized reflectance of the specimen from the measured exposure amounts by using three polarizers, it could not specifically present a Muller matrix measurement method for anisotropic specimens, and accordingly, there was a problem that additional measurements such as rotating the orientation of the specimen or scanning a fixed optical element were required to detect the shape and physical properties of anisotropic specimens. In addition, the aforementioned conventional technology had a problem in that the measurement time was at least 8 times longer than that of a conventional spectroscopic ellipsometer for measuring isotropic optical properties, as two constant-velocity rotating optical elements were respectively positioned in front of and behind the center of the specimen in the optical path of the measurement beam and rotated at a constant rate of an integer multiple of the base rotational time period. (Patent Document 1) Korean Registered Patent Publication No. 10-0701301 (March 22, 2007) FIG. 1 is a schematic diagram showing a single optical element rotary ellipsometer according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing a polarization detector equipped in a single optical element rotary ellipsometer according to the first and second embodiments of the present invention. FIG. 3 is a schematic diagram showing a modified example of a single optical element rotary ellipsometer according to the first embodiment of the present invention. FIG. 4 is a schematic diagram showing a single optical element rotary ellipsometer according to a second embodiment of the present invention. FIG. 5 is a schematic diagram showing a modified example of a single optical element rotary ellipsometer according to a second embodiment of the present invention. The present invention will be described below with reference to the attached drawings. However, the present invention may be implemented in various different forms and is therefore not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals. Throughout the specification, when it is stated that a part is "connected (connected, in contact, combined)" with another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other members interposed between them. Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components. The terms used herein are merely for describing specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In