KR101761251B1 - Spectroscopic ellipsometer - Google Patents

Spectroscopic ellipsometer Download PDF

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KR101761251B1
KR101761251B1 KR1020160027018A KR20160027018A KR101761251B1 KR 101761251 B1 KR101761251 B1 KR 101761251B1 KR 1020160027018 A KR1020160027018 A KR 1020160027018A KR 20160027018 A KR20160027018 A KR 20160027018A KR 101761251 B1 KR101761251 B1 KR 101761251B1
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light
specimen
polarizer
optical
reflected
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KR1020160027018A
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Korean (ko)
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안일신
이창호
김슬기
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한양대학교 에리카산학협력단
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/21—Polarisation-affecting properties
    • G01N21/211—Ellipsometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G01N3/06—Special adaptations of indicating or recording means
    • G01N3/068—Special adaptations of indicating or recording means with optical indicating or recording means
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/55—Specular reflectivity
    • G01N2021/558—Measuring reflectivity and transmission

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  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

The spectroscopic ellipsoidal analyzer includes an optical bench for generating polarized light; An objective mirror system provided between the optical bench and the specimen for causing the polarized light to enter the specimen and causing reflected light reflected from the specimen to enter the optical system; Wherein the optical bench comprises: a light source for emitting light; A polarizer provided between the light source and the objective mirror system for polarizing the light emitted from the light source and analyzing the reflected light reflected from the specimen; And a spectroscope detecting a polarization change amount of the reflected light that has passed through the polarizer; . ≪ / RTI >
According to such a spectroscopic ellipsometer, alignment of optical components is easy by using a single optical band, and a calibration process for finding the position angle of an optical component can be omitted. Further, the optical unit can be rotated by a single driving unit, and the miniaturization of the equipment can be realized.

Description

A spectroscopic ellipsometer

The present invention relates to a spectroscopic ellipsometer using a single optical band.

Ellipsometry has been used since the end of the 19th century when the light incident on the material is reflected or transmitted through the surface of the medium and changes its polarization state depending on the refractive index or thickness of the medium. The optical properties are the analytical method. Among them, the spectroscopic ellipsometry technique measures the change of the polarization state of the reflected or transmitted light after polarized light is incident on the specimen, and the parameters of the elliptical analyzer are obtained for each wavelength and the optical properties of the specimen are analyzed And the thickness of the thin film specimen is extracted. The equipment using such a measuring method is called a spectroscopic ellipsometer.

The conventional spectroscopic ellipsometer as shown in Fig. 1 is a spectroscopic ellipsometer in which two optical units, that is, the optical-side optical unit 10 and the detector-side optical unit 20 form a specific angle? And optical components necessary for each optical system are mounted. For example, a light source 11, a collimation lens 12, and a polarization generator 13 are sequentially mounted on the light source side optical bench 10, and a polarization analyzer 21 and a spectroscope 13 Detector 22 is mounted.

In order to measure the change of the polarization state, the optical-side optical band 10 or the detector-side optical band 20 rotates, and the rotation of the two optical bands is performed independently.

According to the conventional spectroscopic ellipsometry analyzer, since the directions of the two optical bands are bent with respect to the specimen 300, it is difficult to align the optical parts and optical bands, and the width of the entire apparatus is large, which leads to a disadvantage in small-sized modularization. In addition, since the two optical bands rotate independently, it is not easy to set a fixed specific angle (alpha), and a calibration process for finding an initial position angle of the polarization axis in the optical components, that is, the polarization generator 13 and the polarization analyzer 21 is required .

Therefore, there is a need for introducing a new structure of a spectroscopic elliptic analyzer that can easily align and set the angle of the internal structure and can be downsized.

A related prior art is Korean Patent Laid-Open Publication No. 10-2010-0138136 (entitled: Multichannel spectroscopic ellipsometer, published on Dec. 31, 2010).

The present invention seeks to provide a spectroscopic ellipsometer using a single optical band.

In order to solve the above-mentioned problems, the following spectroscopic ellipsometer is provided.

The spectroscopic ellipsoidal analyzer includes an optical bench for generating polarized light; An objective mirror system provided between the optical bench and the specimen for causing the polarized light to enter the specimen and causing reflected light reflected from the specimen to enter the optical system; Wherein the optical bench comprises: a light source for emitting light; A polarizer provided between the light source and the objective mirror system for polarizing the light emitted from the light source and analyzing the reflected light reflected from the specimen; And a spectroscope detecting a polarization change amount of the reflected light that has passed through the polarizer; . ≪ / RTI >

The optical bench can be placed perpendicular to the specimen.

The spectroscopic elliptical interpolator comprises: a slit provided between the polarizer and the objective mirror system and having an opening formed therein; As shown in FIG.

The apertures may be separated into two at predetermined intervals to separate the incident light incident on the specimen and the reflected light reflected from the specimen.

The objective mirror system may include a concave mirror, which is a convex mirror, which is a primary mirror, and a secondary mirror.

The objective mirror system can have a high numerical aperture (high NA) of about 0.9 or less.

The spectroscopic detector can remove the amount of polarization change by the objective mirror system at the polarization change amount of the reflected light that has passed through the polarizer.

The spectroscopic detector can remove the amount of polarization change by the objective mirror system using the following equation (2).

Figure 112016021809618-pat00001

here,

Figure 112016021809618-pat00002
The reflection coefficient by the objective mirror system before entering the specimen,
Figure 112016021809618-pat00003
Is the reflection coefficient of the objective mirror system after reflection on the specimen, and the transmission coefficient
Figure 112016021809618-pat00004
Wow
Figure 112016021809618-pat00005
Is an unknown value and has a constant value C.

The polariser can be rotated about the vertical axis of the specimen as the central axis.

The spectroscopic detector can detect the amount of polarization change using the following equation (5).

Figure 112016021809618-pat00006

Figure 112016021809618-pat00007

Where α 2 and α 4 are the intensity of the reflected light

Figure 112016021809618-pat00008
The normalized Fourier coefficients of the polarizer, θ is the position angle of the polarizer, and I 0 is the average intensity of the reflected light when the polarizer rotates once.

The spectroscopic elliptical interpolator may include a lens system instead of the objective mirror system.

The lens system may include at least one convex lens.

According to such a spectroscopic ellipsometer, alignment of optical components is easy by using a single optical band, and a calibration process for finding the position angle of an optical component can be omitted. Further, the optical unit can be rotated by a single driving unit, and the miniaturization of the equipment can be realized.

Fig. 1 is a diagram illustrating a configuration of a conventional spectroscopic ellipsometer.
2 is an external view of a spectroscopic ellipsometer according to an embodiment of the present invention.
2 is an internal cross-sectional view of a spectroscopic ellipsometer according to an embodiment.
4 is an internal cross-sectional view of a spectroscopic ellipsometer according to another embodiment.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory only and are not restrictive of the invention, as claimed, and it is to be understood that the invention is not limited to the disclosed embodiments.

Hereinafter, the spectroscopic ellipsometer will be described in detail with reference to the accompanying drawings. Like numbers refer to like elements throughout the drawings.

FIG. 2 is an external perspective view of a spectroscopic ellipsometer according to an embodiment of the present invention, and FIG. 3 is an internal sectional view of a spectroscopic ellipsometer according to an embodiment.

2 and 3, the spectroscopic ellipsometer according to the embodiment includes the optical bench 100 and the objective mirror system 300 to generate polarized light in the specimen 300 placed on the stage 400 And the amount of polarization change of the light reflected therefrom is measured to measure the optical characteristics of the test piece 300, the thickness of the thin film, and the like.

The stage 400 is a space in which the test piece 300 is placed, and the test piece 300 is fixedly installed on the stage 400 so as not to move. The stage 400 is movable in the horizontal direction so that the position of the specimen 300 can be adjusted as the stage 400 moves.

The optical bench 100 has a configuration in which the optical-side optical bench 10 and the detector-side optical bench 20 shown in FIG. 1 are combined into one unit, and is arranged perpendicular to the specimen 300. The optical bench 100 includes a light source 110, a collimator 120, a light splitter 130, a spectroscope detector 140, a polarizer 150 and a slit 160 to generate polarized light, (300), and analyzes the amount of change in polarization state of the light reflected from the specimen (300).

The light source 110 is provided as a white light source such as a halogen lamp, a Xe arc lamp, a deuterium lamp, etc. The white light emitted from the light source 110 passes through the collimator 120 And converted into parallel light or divergent light.

The light splitter 130 is configured to reflect or transmit light, and a light separation prism, a semi-transmissive light separation plate, or the like can be employed. The ratio of the reflectance and the transmittance of the optical splitter 130 is not particularly limited, and for example, a reflectance and a transmittance of 1: 1 can be used. The light splitter 130 may transmit the light passing through the collimator 120 and reflect the light reflected from the specimen 300 to separate the incident light and the reflected light.

3 shows only the optical splitter 130. However, the optical bench 100 may include a shutter that physically opens or closes the progress of the light instead of the optical splitter 130. FIG. Alternatively, the optical bench 100 may include both the optical splitter 130 and the switch.

The polarizer 150 constitutes the polarization generator 13 of FIG. 1 and constitutes the polarization analyzer 21. That is, the polarizer 150 has a structure in which the polarization generator 13 and the polarization analyzer 21 are combined into a single unit. The polarizer 150 polarizes the light incident on the specimen 300, The polarized light is separated into two polarized lights. The polarizer 150 performs the function of the polarization generator 13 in the path on which the light is incident to the test piece 300 and the polarization analyzer 21 in the path on which the light is emitted from the test piece 300.

The polarizer 150 may be formed of a material having a birefringent property and may be formed by joining two triangular prisms whose refractive index directions are different from each other. The polarization generator 130 may be made of magnesium fluoride so as to transmit light in a wide spectral range.

Although FIG. 3 shows only the polarizer 150, the optical bench 100 may further include a retarder in addition to the polarizer 150. FIG.

The optical bench 100 may include a slit 160. At this time, the slit 160 forms the opening h, and the size of the opening h may be about several tens of micrometers. The slit 160 can selectively pass light by forming the aperture h in this way. Further, the openings h are provided separately in two at a predetermined interval, so that incident light and reflected light can be separated. The spacing between the openings h may be adjustable according to the characteristics of the specimen 300, the structure and characteristics of the objective mirror system 200, the distance between the specimen 300 and the objective mirror system 200, And the opening h, the incident angle alpha of the light incident on the specimen 300 can be adjusted.

Here, the incident angle is defined as an angle formed by the vertical axis of the specimen 300 and the incident light incident on the specimen 300, and means the degree of incidence of the incident light from the specimen 300.

Light incident from the light source 110 and the collimator 120 is polarized in a specific polarization state while passing through the polarizer 150 and light polarized through the polarizer 150 passes through the slit 160 and the objective mirror system 200 And then enters the specimen 300. The incident angle?

The objective mirror system 200 may include a primary mirror 202, which is a convex mirror, and a secondary mirror 201, which is a concave mirror. The primary mirror 202 is formed on the center axis of the objective mirror system 200 and the secondary mirror 201 can be formed separately on both sides of the primary mirror 202. [

The light incident from the direction of the light source 110 is primarily reflected by the primary mirror 202 and then incident on the secondary mirror 201. The light reflected by the secondary mirror 201 forms an incident angle alpha and is focused on the specimen 300. On the other hand, the light reflected from the specimen 300 is firstly reflected by the secondary mirror 201 and then incident on the primary mirror 201. The light reflected on the primary mirror 201 is directed to the polarizer 150 via the slit 160.

The objective mirror system 200 adopts a high numerical aperture (high NA) of about 0.9 or more, and can satisfy an incident angle of about 70 ° required by the elliptic interpolator. In order to improve the measurement sensitivity, it is necessary to adjust the incident angle to about 65 ° to 75 ° according to the specimen 300. The spectroscopic ellipsometer uses numerical aperture (NA) or numerical aperture The interval between the openings h of the slit 160 can be changed to adjust the incident angle to be suitable for the measurement sensitivity.

The light that has reached the polarizer 150 through the objective mirror system 200 and the slit 160 is split into two polarized lights whose directions of vibration are perpendicular to each other and reflected by the light splitter 130 to be incident on the spectral detector 140 .

The spectroscopic detector 140 may employ various types of devices such as a CCD (Charge Coupled Device) or a photodiode. The amount of change in the polarization state is calculated using the separated polarization components, And the thickness of the thin film.

The spectroscopic detector 140 can calculate the variable {[Delta], [Psi]) of the elliptical interpolator with respect to the specimen 300 as the amount of change in polarization state. {[Delta], [Psi]} has a relational expression as shown in the following equation (1).

[Equation 1]

Figure 112016021809618-pat00009

Where Rp is the reflection coefficient for the polarization parallel to the incident surface of the specimen and Rs is the reflection coefficient for the polarization perpendicular to the incident surface of the specimen.

On the other hand, when the light enters the mirror or the surface of the lens at a large incident angle, the polarization changes, and this change amount is mixed with the polarization change amount generated by the test piece 300. Therefore, the spectroscopic detector 140 performs a process of calculating the amount of polarization change by the sample 300 by removing the polarization change amount generated by the mirror or the lens from the measured value. Spectroscopic ellipsometer according to one embodiment is to include an objective mirror system 200, in the spectral detector 140 the measured polarization change amount {Δ C, Ψ C}, the polarization change amount of the objective mirror system 200 And the amount of polarization change [Delta], [Psi] by the pure specimen 300 is calculated.

The reflection coefficient in the specimen 300, which corresponds to the amount of polarization change? And? By the specimen 300,

Figure 112016021809618-pat00010
. Further, the reflection coefficient of the objective mirror system 200 before entering the specimen 300
Figure 112016021809618-pat00011
A reflection coefficient of the objective mirror system 200 after reflection to the specimen 300,
Figure 112016021809618-pat00012
Is expressed in conjunction with the reflection coefficient of the test piece 300
Figure 112016021809618-pat00013
.

Here,

Figure 112017049701597-pat00014
Wow
Figure 112017049701597-pat00015
And these values are represented by a predetermined constant value (C) unless there is a change in the objective mirror system 200. Thus, the measured polarization change amount Δ {C, C Ψ} forms a relationship, such as Equation 2 below.

&Quot; (2) "

Figure 112016021809618-pat00016

Here, the unknown value C is found by using a material having a well-known optical property. That is, the polarization variation {Δ C , Ψ C } measured using a well-known material and the theoretical value

Figure 112016021809618-pat00017
, The unknown C value can be calculated.

Then, by removing the C value calculated from the measured polarization change amount {[Delta] C , [Psi C] },

Figure 112016021809618-pat00018
Or {Δ, Ψ}.

The spectroscopic ellipsometer can rotate the polarizer 150 about the vertical axis of the specimen 300 as a central axis for measuring the change amount of the polarization state. As described above, the polarizer 150 has a structure in which the polarization generator 13 and the polarization analyzer 21 are combined into one unit. The rotation of the polarizer 150 rotates the polarization generator 13 and the polarization analyzer 21 at the same time .

The spectroscopic ellipsometer may further include a stepping motor coupled to the polariser 150, and may apply a motor drive pulse to rotate the stepping motor. The stepping motor rotates by a unit angle every time a motor driving pulse is applied, and the polarizer 150 coupled to the stepping motor rotates in accordance with the rotation of the stepping motor.

The polarization direction of the light passing through the polarizer 150 by the rotation of the stepping motor periodically changes. Since the polarization generator 13 and the polarization analyzer 21 are replaced by a single polarizer 150, the waveform of the incident light incident on the specimen 300 through the polarizer 150 and the waveform of the incident light incident on the specimen 300 through the polarizer 150 The reflected wave of the reflected light has the same shape and the same period.

The intensity I of light (e.g., reflected light) at the position angle [theta] of the polarizer 150 can be expressed by the following equation (3).

&Quot; (3) "

Figure 112016021809618-pat00019

Here, I 0 denotes the average intensity of light when the polarizer 150 makes one revolution, and α 2 and α 4 denote the normalized Fourier coefficients.

In addition, the unit Fourier coefficients? 2 and? 4 can be expressed by the following Equation (4).

&Quot; (4) "

Figure 112016021809618-pat00020
,

Figure 112016021809618-pat00021

The spectroscopic detector 220 can measure the intensity of the reflected light and calculate the polarization change amount DELTA, DELTA, as shown in the following equation (5) by using the equations (3) and (4)

&Quot; (5) "

Figure 112016021809618-pat00022
,

Figure 112016021809618-pat00023

As described above with reference to FIG. 1, when the polarization generator 13 and the polarization analyzer 21 rotate independently, a calibration process is required. The calibration is a line measurement process prior to the measurement of the elliptic interpolator in the process of finding the initial position angle of the polarization axis in the polarization generator 13 and the polarization analyzer 21. The calibration process takes a long time to measure, and is reflected in the measured value when an error occurs.

In contrast, a spectroscopic ellipsometer according to one embodiment may rotate a single polarizer 150. The rotation of the single polarizer 150 is equivalent to rotating the polarization generator 13 and the polarization analyzer 21 at the same time so that the spectroscopic detector 220 can calculate the polarization It is possible to calculate the change amount {[Delta], [Psi]}.

2 and 3, a spectroscopic ellipsometer according to an embodiment of the present invention has been described. Hereinafter, a spectroscopic ellipsometer according to another embodiment will be described in detail with reference to FIG. In the description of FIG. 4, the same configuration as that of the above-described embodiment and its detailed description will be omitted below.

4 is an internal cross-sectional view of a spectroscopic ellipsometer according to another embodiment.

4, a spectroscopic ellipsometry analyzer according to another embodiment includes polarized light generated by a specimen 300 placed on a stage 400 including an optical system 100 and an objective lens system 210, The optical characteristics of the specimen 300, the thickness of the thin film, and the like are measured by measuring the amount of polarization change of the reflected light.

The optical bench 100 constitutes a single optical bench 100 arranged vertically with the specimen 300. The optical system 100 includes a light source 110, a collimator 120, a light splitter 130, a spectroscope detector 140, a polarization generator 150, and a slit 160 to generate polarized light Is incident on the specimen (300), and the amount of change in polarization state of the light reflected from the specimen (300) is analyzed.

The light source 110 may be a white light source, for example, a halogen lamp, a Xe arc lamp, a deuterium lamp, or the like. The collimator 120 converts the white light emitted from the light source 110 into a parallel light or a divergent light.

The light splitter 130 is configured to reflect or transmit light, and a light separation prism, a semi-transmissive light separation plate, or the like can be employed. The light splitter 130 can separate the incident light and the reflected light as the light passing through the collimator 120 is transmitted and the light reflected from the specimen 300 is reflected. The reflectance and transmittance of the light splitter 130 The ratio is not particularly limited.

4 shows only the optical splitter 130. However, the optical bench 100 may include a shutter that physically opens or closes the progress of light instead of the optical splitter 130. FIG. Alternatively, the optical bench 100 may include both the optical splitter 130 and the switch.

The polarizer 150 is a constitution in which the polarization generator 13 and the polarization analyzer 21 of FIG. 1 are combined into one unit. The polarizer 150 polarizes the light incident on the sample 300, Separate into two vertical polarizations. That is, the polarizer 150 performs the function of the polarization generator 13 in the path on which the light is incident to the test piece 300, and the polarization analyzer 21 in the path on which the light is emitted from the test piece 300.

The polarizer 150 may be formed of a material having a birefringent property and may be formed by joining two triangular prisms whose refractive index directions are different from each other. The polarization generator 130 may be made of magnesium fluoride so as to transmit light in a wide spectral range.

Although FIG. 4 shows only the polarizer 150, the optical bench 100 may further include a retarder in addition to the polarizer 150. FIG.

The optical system 100 includes a slit 160 on the optical path between the polarizer 150 and the objective lens system 210 and the slit 160 forms an opening h of a size on the order of several tens of micrometers. The slit 160 can selectively pass light through such an opening h and can adjust the amount of light passing or the range of light by adjusting the size of the opening h. The openings h are provided separately in two at predetermined intervals, so that incident light and reflected light can be separated. The spacing between the openings h may be adjustable depending on the characteristics of the test piece 300, the structure and characteristics of the objective lens system 210, the distance between the specimen 300 and the objective lens system 210, the angle of incidence? of light incident on the specimen 300 can be adjusted by adjusting the interval between the first and second surfaces h.

The objective lens system 210 includes a convex lens. The objective lens system 210 may include a plurality of convex lenses. In this case, the plurality of convex lenses may have a laminated structure in which light is incident or reflected. The objective lens system 210 may be composed of a single convex lens, unlike the example shown in FIG.

The objective lens system 210 can adopt a high numerical aperture (high NA) of about 0.9 or more to satisfy an incident angle of about 70 degrees required by the elliptical interpolator. In order to improve the measurement sensitivity of the elliptic interpolator, it is necessary to adjust the incident angle in the range of about 65 ° to 75 ° according to the specimen 300. The spectroscopic ellipsometry analyzer has a numerical aperture (NA) The interval can be changed to adjust the angle of incidence suitable for the measurement sensitivity.

Although the spectroscopic ellipsometer according to another embodiment includes the objective lens system 210, it is also possible to construct a camera lens system in place of the objective lens system 210.

The white light emitted from the light source 110 is converted into parallel light by the collimator 120. The parallel light passes through the light splitter 130 and enters the polarizer 150. [ The light incident on the polarizer 150 is biased to one side from the center of the polarizer 150 and enters. The light passing through the polarizer 150 is polarized and passes through one of the two openings h of the slit 160, so that the cross section of the light becomes small. The light passing through the slit 160 passes through one side of the objective lens system 210 and is incident on the specimen 300 at a specific incident angle?. The light reflected from the specimen 300 passes again through the objective lens system 210 and another opening of the slit 160 and then through the polarizer 150. At this time, the direction of the light passing therethrough proceeds in a direction opposite to the direction of incidence, and the polarizer 150 functions as the polarization analyzer 21 of FIG. The light having passed through the polarizer 160 reaches the spectroscopic detector 140 via the light splitter 130, and the light amount of each wavelength is measured.

The spectroscopic ellipsometer may further include a stepping motor coupled to the polarizer 150, which may rotate the polarizer 150 about the vertical axis of the specimen 300 by driving it. The stepping motor rotates by a unit angle every time a motor driving pulse is applied, and the polarizer 150 coupled to the stepping motor rotates in accordance with the rotation of the stepping motor.

The rotation of the single polarizer 150 is the same as rotating the polarization generator 13 and the polarization analyzer 21 at the same time so that the spectroscopic detector 140 can skip the calibration process. That is, the polarizer 150 is used while measuring a plurality of light amount, and the spectral detector 140, a plurality of measured values and the above-described [Equation 5] rotation and calculates the polarization change amount by {Δ C, Ψ C} . The polarization change amount thus calculated can be defined as the " measured polarization change amount ".

The spectroscopic detector 140 removes the amount of polarization change generated by the lens from the measured value and performs a process of calculating the amount of polarization change by the test piece 300 purely. The spectroscopic detector 140 calculates the amount of polarization change?,? By the specimen 300 using the above-described expression (2). In this case, Equation (2) can be re-expressed as follows for the objective lens system 210 as appropriate.

&Quot; (2) "

Figure 112016021809618-pat00024

here,

Figure 112017049701597-pat00025
The transmission coefficient by the objective lens system 210 before entering the specimen 300,
Figure 112017049701597-pat00026
Means the transmission coefficient by the objective lens system 220 after reflection to the specimen 300, and the transmission coefficient
Figure 112017049701597-pat00027
Wow
Figure 112017049701597-pat00028
And these values are represented by a predetermined constant value C unless the objective lens system 210 has a change.

The unknown C value can be found using materials with well-known optical properties. That is, the polarization variation {Δ C , Ψ C } measured using a well-known material and the theoretical value

Figure 112016021809618-pat00029
, The unknown C value can be calculated.

The spectroscopic detector 140 removes the C value calculated from the measured polarization change amounts {Delta C , [Delta] C }

Figure 112016021809618-pat00030
Or {?,?}.

The spectroscopic detector 140 obtains information on the optical characteristics of the sample 300 and the thickness of the thin film by calculating the amount of polarization change Δ and Ψ by the specimen and uses a charge coupled device (CCD) or a photodiode photodiode) may be employed.

While the embodiments of the spectroscopic ellipsometer have been described with reference to the drawings exemplified above, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. It will be understood that the invention may be practiced. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

100: optical band 110: light source
120: collimator 130: light splitter
140: Spectroscopic detector 150: Polarizer
160: slit 200: object mirror system
210: objective lens system 300: specimen

Claims (12)

An optical bench for generating polarized light; And
An objective mirror system provided between the optical bench and the specimen for causing the polarized light to enter the specimen and causing reflected light reflected from the specimen to enter the optical system; Lt; / RTI >
The optical unit includes:
A light source for emitting light;
A polarizer provided between the light source and the objective mirror system for polarizing the light emitted from the light source and analyzing the reflected light reflected from the specimen;
A spectroscope detecting a polarization change amount of the reflected light having passed through the polarizer;
And
A slit provided between the polarizer and the objective mirror system and having an opening formed therein;
/ RTI >
The opening
And separating the incident light incident on the specimen and the reflected light reflected from the specimen. The method according to claim 1,
The optical unit includes:
And a spectral ellipsometer disposed perpendicular to the specimen. delete delete The method according to claim 1,
The objective mirror system includes:
A spectroscopic ellipsometer comprising a convex mirror as a primary mirror and a concave mirror as a secondary mirror. The method according to claim 1,
The objective mirror system includes:
A spectroscopic ellipsometer with a high numerical aperture (high NA) of around 0.9. The method according to claim 1,
The spectroscopic detector comprises:
And a polarization change amount by the objective mirror system is removed from the polarization change amount of the reflected light that has passed through the polarizer. 8. The method of claim 7,
The spectroscopic detector comprises:
A spectroscopic ellipsometer for removing the amount of polarization change by the objective mirror system using the following equation (2).

&Quot; (2) "
Figure 112017049701597-pat00031


here,
Figure 112017049701597-pat00032
The reflection coefficient by the objective mirror system before entering the specimen,
Figure 112017049701597-pat00033
Is the reflection coefficient of the objective mirror system after reflection on the specimen, and the reflection coefficient
Figure 112017049701597-pat00034
Wow
Figure 112017049701597-pat00035
Is expressed by a predetermined constant value C as an unknown number. The method according to claim 1,
The polarizer comprises:
And the spectral ellipsometer is rotated around the vertical axis of the specimen as a center axis. 10. The method of claim 9,
The spectroscopic detector comprises:
A spectroscopic ellipsometer for detecting the amount of polarization change using the following equation (5).

&Quot; (5) "
Figure 112016021809618-pat00036
,
Figure 112016021809618-pat00037


Here,? 2 and? 4 are the intensity of the reflected light
Figure 112016021809618-pat00038
The normalized Fourier coefficients of the polarizer,? Represents the positional angle of the polarizer, and I 0 represents the average intensity of the reflected light when the polarizer rotates once. The method according to claim 1,
Wherein the spectral ellipsometer includes a lens system instead of the objective mirror system. 12. The method of claim 11,
The lens system includes:
A spectral ellipsometer comprising at least one convex lens.
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KR20200126558A (en) 2019-04-30 2020-11-09 (주)엘립소테크놀러지 Method for measuring the light intensity of continuous rotation of a polarizer
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Cited By (10)

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Publication number Priority date Publication date Assignee Title
KR20190079143A (en) * 2017-12-27 2019-07-05 한양대학교 에리카산학협력단 Ellipsometer
KR102016452B1 (en) * 2017-12-27 2019-08-30 한양대학교 에리카산학협력단 Ellipsometer
US10969329B2 (en) 2018-05-28 2021-04-06 Samsung Display Co., Ltd. Ellipsometer
KR20200074708A (en) * 2018-12-17 2020-06-25 한양대학교 에리카산학협력단 Ellipsometer and The Module for Reflecting Polarized Light
KR102137053B1 (en) * 2018-12-17 2020-07-23 한양대학교 에리카산학협력단 Ellipsometer and The Module for Reflecting Polarized Light
KR20200080767A (en) * 2018-12-27 2020-07-07 한양대학교 에리카산학협력단 Spectroscopic Ellipsometer
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KR20200126550A (en) 2019-04-30 2020-11-09 (주)엘립소테크놀러지 Continuously measurable spectroscopic ellipsometer
KR20200126558A (en) 2019-04-30 2020-11-09 (주)엘립소테크놀러지 Method for measuring the light intensity of continuous rotation of a polarizer
KR102195132B1 (en) 2019-04-30 2020-12-24 (주)엘립소테크놀러지 Method for measuring the light intensity of continuous rotation of a polarizer

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