Elliptic polarization measuring system and measuring method

Abstract

The invention discloses an ellipsometry system and method which can be applied to the technical field of optics, and the system comprises an irradiation assembly and a light receiving assembly. The irradiation assembly is arranged at the first inclined upper part of the first plane side of the to-be-detected sample and is used for generating a polarization diffraction beam and obliquely irradiating the polarization diffraction beam to the to-be-detected sample; the to-be-tested sample is used for reflecting the polarization diffraction light beam and generating a signal light beam; the light receiving assembly is arranged on the second inclined upper side of the first plane side of the to-be-detected sample and is used for receiving the signal light beam and separating effective irradiation light and diffraction stray light in the signal light beam; the effective irradiation light and the diffraction stray light are respectively used for determining optical information and height information of the sample to be detected by the light receiving assembly. Thus, effective irradiation light and diffraction stray light can be generated and separated through cooperation of the irradiation assembly and the light receiving assembly, and then the effective irradiation light and the diffraction stray light are respectively used for measuring optical information and height information of the sample to be measured, and the measurement accuracy of the ellipsometry system is guaranteed.

Description

Technical Field

[0001] This application relates to the field of optical technologies, and particularly to an ellipsometry system and a measurement method. Background Art

[0002] Ellipsometry is used to detect film thickness, optical constants, and material microstructures, etc. As an ellipsometry instrument, the ellipsometer has become an extremely attractive measurement device due to its high measurement accuracy of film thickness and refractive index, non-contact with the sample, no damage to the sample, and no need for vacuum, etc.

[0003] The height position of the sample in the ellipsometer is particularly crucial. When the existing ellipsometer is in use, it should ensure that the sample surface is at the focus position of the objective lens. However, since the existing ellipsometry system cannot measure the height position of the sample by itself. The height position error in the measurement area of the sample surface will cause problems such as a larger irradiation spot, incomplete light collection, and changes in the irradiation position, etc., thus resulting in differences in the collected data and inaccurate measurement results.

[0004] Therefore, how to ensure the measurement accuracy of the ellipsometry system is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] Based on the above problems, this application provides an ellipsometry system and a measurement method. By the cooperation of the irradiation component and the light collection component, effective irradiation light and diffracted stray light can be generated and separated, and then used to measure the optical information and height information of the sample to be measured respectively, ensuring the measurement accuracy of the ellipsometry system.

[0006] In a first aspect, an embodiment of this application provides an ellipsometry system, including: an irradiation component and a light collection component;

[0007] The irradiation component is arranged obliquely above the first plane side of the sample to be measured, and is used to generate a polarized diffracted light beam and obliquely irradiate the polarized diffracted light beam onto the sample to be measured;

[0008] The sample to be measured is used to reflect the polarized diffracted light beam and generate a signal light beam;

[0009] The light collection component is arranged obliquely above the second plane side of the sample to be measured, and is used to receive the signal light beam and separate the effective irradiation light and diffracted stray light in the signal light beam; the effective irradiation light and the diffracted stray light are respectively used by the light collection component to determine the optical information and height information of the sample to be measured.

[0010] Optionally, the irradiation component includes: a light beam generation component and a light beam adjustment component;

[0011] The beam generating component includes: a light source, an ellipsoidal mirror, and a field stop;

[0012] The ellipsoidal mirror is used to reflect the light emitted by the light source and focus it on the small hole of the field stop, generating a divergent beam; the light source is a broadband light source; the light emitted by the broadband light source is in the ultraviolet to infrared band;

[0013] The beam adjusting component is arranged in the optical path of the divergent beam and is used to adjust the irradiation spot formed by the divergent beam on the sample to be measured.

[0014] Optionally, the beam adjusting component includes: a first polarizer;

[0015] The first polarizer is arranged at the end of the optical path of the divergent beam that is farthest from the field stop and is used to adjust the polarization state of the divergent beam to form a polarized spot on the sample to be measured.

[0016] Optionally, the beam adjusting component includes: a serrated aperture;

[0017] The serrated aperture is arranged between the field stop and the first polarizer in the optical path of the divergent beam and is used to reduce the numerical aperture of the optical path of the divergent beam and suppress Fresnel diffraction.

[0018] Optionally, the beam adjusting component includes: a first broadband achromatic lens;

[0019] The first broadband achromatic lens is arranged between the field stop and the first polarizer in the optical path of the divergent beam.

[0020] Optionally, the light receiving component includes: a second broadband achromatic lens, a second polarizer, a separation component, a spectral detection module, and a calibration module;

[0021] The second broadband achromatic lens, the second polarizer, and the separation component are sequentially arranged in the optical path of the signal beam along the propagation direction of the signal beam;

[0022] The separation component is used to separate the diffracted stray light in the signal beam, control the diffracted stray light to be incident on the calibration module, and control the effective irradiation light in the signal beam to be incident on the spectral detection module.

[0023] Optionally, the second polarizer is a rotatable Glan-Taylor polarizing prism, serving as a rotating analyzer.

[0024] Optionally, the separation component includes a first part and a second part arranged sequentially in the circumferential direction. The first part is configured to guide the effective irradiation light at the center of the signal beam to the spectral detection module in a reflective or transmissive manner, and the second part is located outside the first part and is configured to guide the diffracted stray light outside the signal beam to the calibration module in a reflective or transmissive manner.

[0025] Optionally, the light receiving component further includes: a beam splitting component; the spectral detection module includes: a first spectrometer and a second spectrometer; the first spectrometer is a first band response wavelength spectrometer with a spectral resolution < 4 nm; the second spectrometer is a second band response wavelength spectrometer with a spectral resolution < 8 nm; the wavelength in the first band is less than the wavelength in the second band;

[0026] The beam splitting component is disposed between the second polarizer and the separation component in the optical path of the signal beam and is configured to split the signal beam into a second signal sub-beam and a first signal sub-beam;

[0027] The first signal sub-beam is incident on the first spectrometer;

[0028] The second signal sub-beam is incident on the second spectrometer.

[0029] Optionally, the beam splitting component is a dot beam splitter, which is composed of a UV-grade fused silica substrate and an array of enhanced aluminum films evenly deposited on the fused silica substrate;

[0030] The incident angle of the signal beam on the beam splitting component is 45°.

[0031] Optionally, the separation component includes: a first filtering component and a second filtering component; the calibration module includes: a first detector and a second detector;

[0032] The first filtering component is configured to filter the first signal sub-beam and direct the first diffracted stray light in the first signal sub-beam to the first detector; the band of the first diffracted stray light is the first band;

[0033] The second filtering component is configured to filter the second signal sub-beam and direct the second diffracted stray light in the second signal sub-beam to the second detector; the band of the second diffracted stray light is the second band.

[0034] Optionally, the first filtering component includes a third part and a fourth part arranged sequentially in the circumferential direction. The third part is configured to guide the effective irradiation light at the center of the first signal sub-beam to the first spectrometer in a reflective or transmissive manner. The fourth part is located outside the third part and is configured to guide the diffracted stray light outside the first signal sub-beam to the first detector in a reflective or transmissive manner;

[0035] The second filtering component includes a fifth part and a sixth part arranged sequentially in the circumferential direction. The fifth part is configured to guide the effective irradiation light at the center of the second signal sub-beam to the second spectrometer in a reflective or transmissive manner. The sixth part is located outside the fifth part and is configured to guide the diffracted stray light outside the second signal sub-beam to the second detector in a reflective or transmissive manner.

[0036] Optionally, the first filtering component is composed of a first small aperture diaphragm or a first mirror. When the first filtering component is the first small aperture diaphragm, the third part is a small hole with a size of 60um * 120um, and the fourth part is an ultraviolet-enhanced aluminum film plated on the quartz substrate outside the small hole. When the first filtering component is the first mirror, the third part is a first reflective metal film with a size of 60um * 120um plated in the middle, and the fourth part is a lens outside the first reflective metal film;

[0037] The second filtering component is composed of a second small aperture diaphragm or a second mirror. When the second filtering component is the second small aperture diaphragm, the fifth part is a small hole with a size of 80um * 160um, and the sixth part is an infrared-enhanced silver film plated on the quartz substrate outside the small hole. When the second filtering component is the second mirror, the fifth part is a second reflective metal film with a size of 80um * 160um plated in the middle, and the sixth part is a lens outside the second reflective metal film.

[0038] Optionally, the calibration module includes: a first filter and a first condenser lens corresponding to the first detector, and a second filter and a second condenser lens corresponding to the second detector;

[0039] The first filter, the first condenser lens, and the first detector are sequentially arranged in the optical path of the first diffracted stray light along the propagation direction of the first diffracted stray light;

[0040] The first filter is a narrowband filter in the third band, which is used to limit the wavelength of the first diffracted stray light; the third band is within the first band;

[0041] The first condenser lens is used to converge the first diffracted stray light with the limited wavelength onto the first detector;

[0042] The second filter, the second condenser, and the second detector are sequentially arranged in the optical path of the second diffracted stray light along the propagation direction of the second diffracted stray light;

[0043] The second filter is a narrowband filter in the fourth band, which is used to limit the wavelength of the second diffracted stray light; the fourth band is within the second band;

[0044] The second condenser is used to converge the second diffracted stray light with the limited wavelength onto the second detector.

[0045] In a second aspect, an embodiment of the present application provides a measurement method for an ellipsometry system. The system includes an illumination component and a light receiving component. The measurement method includes:

[0046] Configure the illumination component so that the polarized diffracted light beam generated by the illumination component can irradiate the sample to be measured and generate a signal light beam;

[0047] Set the light receiving component in the optical path of the signal light beam so that the light receiving component can receive the signal light beam and separate the effective irradiation light and the diffracted stray light in the signal light beam;

[0048] Use the light receiving component to determine the optical information of the sample to be measured according to the effective irradiation light, and determine the height information of the sample to be measured according to the diffracted stray light.

[0049] It can be seen from the above technical solutions that compared with the prior art, the present application has the following advantages:

[0050] An ellipsometry system and a measurement method provided by the present application, the system comprising: an irradiation component and a light receiving component; the irradiation component is disposed obliquely above the first plane side of the sample to be measured, and is used for generating a polarized diffraction beam and obliquely irradiating the polarized diffraction beam onto the sample to be measured; the sample to be measured is used for reflecting the polarized diffraction beam and generating a signal beam; the light receiving component is disposed obliquely above the second plane side of the sample to be measured, and is used for receiving the signal beam and separating the effective irradiation light and the diffracted stray light in the signal beam; the effective irradiation light and the diffracted stray light are respectively used by the light receiving component to determine the optical information and the height information of the sample to be measured. Since the diffracted stray light and the effective irradiation light spot are coaxial light beams, changes in the devices in the optical path have the same effect on the diffracted stray light and the film thickness detection irradiation light spot. In the present application, the incident optical paths of the focusing optical path and the spectral detection optical path share the same optical path, are not affected by the external environment, can realize on-line in-situ calibration and calibration of the height position of the sample, and do not affect the light intensity. Thus, the irradiation component can generate a higher light intensity and a smaller size light spot to irradiate on the sample to be measured, and then through the cooperation of the irradiation component and the light receiving component, the effective irradiation light and the diffracted stray light can be separated, and then used to measure the optical information and the height information of the sample to be measured respectively. Through separated detection, the diffracted stray light irradiated outside the sample measurement area is avoided from affecting the optical information detection, and the effective light for measuring the optical information of the sample to be measured is not lost, ensuring the measurement accuracy of the ellipsometry system. Description of the Drawings

[0051] Figure 1 It is a schematic structural diagram of an ellipsometry system provided by an embodiment of the present application;

[0052] Figure 2 It is a schematic structural diagram of an irradiation component provided by an embodiment of the present application;

[0053] Figure 3 It is a schematic diagram of the position setting of a first polarizer provided by an embodiment of the present application;

[0054] Figure 4 It is a schematic structural diagram of a sawtooth aperture provided by an embodiment of the present application;

[0055] Figure 5 It is a schematic diagram of chromatic focal shift provided by an embodiment of the present application;

[0056] Figure 6 It is a schematic structural diagram of a light receiving component provided by an embodiment of the present application;

[0057] Figure 7 It is a schematic structural diagram of a light receiving component with a beam splitting component provided by an embodiment of the present application;

[0058] Figure 8 It is a schematic diagram of small apertures with two different processes provided by an embodiment of the present application;

[0059] Figure 9 Schematic diagram of an irradiation spot provided by an embodiment of the present application;

[0060] Figure 10 Optical path schematic diagram of an ellipsometry system provided by an embodiment of the present application;

[0061] Figure 11 Flowchart of a measurement method for an ellipsometry system provided by an embodiment of the present application;

[0062] Figure 12 PSF cross-sectional diagrams with and without a serrated aperture under different wavelength bands provided by an embodiment of the present application;

[0063] Figure 13 Schematic diagram of the relationship between the sample height and the centroid of the light spot provided by an embodiment of the present application. Detailed implementation manners

[0064] As described above, the existing ellipsometry system has the problem of inaccurate measurement results. Specifically, the lateral resolution of the ellipsometer is mainly determined by the irradiation spot. As the size of the sample to be measured becomes smaller and smaller, the traditional ellipsometry system cannot accurately focus the light beam on the surface of the sample, so that the surface of the sample is at the focal position of the objective lens. After the system is fixed, the height of the calibration sample is adjusted to make the light beam focus on the surface of the sample. However, the common method for calibrating the height of the measurement area on the surface of the calibration sample in the existing ellipsometry system is to install an independent focal length measurement module. However, due to structural interference and environmental differences, the light spot of the ranging and angle measurement module cannot coincide with the light spot of the ellipsometry measurement, which leads to the problem of poor measurement accuracy of the ellipsometry system.

[0065] To solve the above problems, the present application provides an ellipsometry system, including: an irradiation component and a light receiving component; the irradiation component is arranged obliquely above the first plane side of the sample to be measured, and is used to generate a polarized diffraction light beam and obliquely irradiate the polarized diffraction light beam on the sample to be measured; the sample to be measured is used to reflect the polarized diffraction light beam and generate a signal light beam; the light receiving component is arranged obliquely above the second plane side of the sample to be measured, and is used to receive the signal light beam and separate the effective irradiation light and the diffracted stray light in the signal light beam; the effective irradiation light and the diffracted stray light are respectively used by the light receiving component to determine the optical information and height information of the sample to be measured.

[0066] In this way, the irradiation component can generate a light spot with higher light intensity and smaller size to irradiate the sample to be measured. Then, through the cooperation of the irradiation component and the light collection component, the effective irradiation light and the diffracted stray light can be generated and separated, and are respectively used to measure the optical information and height information of the sample to be measured. By separating the detection, the influence of the diffracted stray light on the detection of optical information is avoided, and the effective light for measuring the optical information of the sample to be measured is not lost, ensuring the measurement accuracy of the ellipsometry system. The diffracted stray light and the effective irradiation light spot are coaxial light beams. Changes in the devices in the optical path have the same influence on the diffracted stray light and the irradiation light spot for film thickness detection, and on-line in-situ calibration and calibration of the height position of the sample can be realized.

[0067] It should be noted that an ellipsometry system and a measurement method provided by the present application can be applied to the field of optical technology. The above is only an example and does not limit the application field of an ellipsometry system and a measurement method provided by the present application.

[0068] In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0069] Figure 1 It is a schematic structural diagram of an ellipsometry system provided by an embodiment of the present application. Combining Figure 1 As shown, an ellipsometry system 100 provided by an embodiment of the present application includes: an irradiation component 110 and a light collection component 120;

[0070] The irradiation component 110 is arranged obliquely above the first plane side of the sample to be measured, and is used to generate a polarized diffracted light beam and obliquely irradiate the polarized diffracted light beam onto the sample to be measured;

[0071] The sample to be measured is used to reflect the polarized diffracted light beam and generate a signal light beam;

[0072] The light collection component 120 is arranged obliquely above the second plane side of the sample to be measured, and is used to receive the signal light beam and separate the effective irradiation light and the diffracted stray light in the signal light beam; the effective irradiation light and the diffracted stray light are respectively used by the light collection component 120 to determine the optical information and height information of the sample to be measured.

[0073] Specifically, the specimen stage is set horizontally, and the specimen to be measured is placed on the specimen stage. The specimen stage can drive the specimen to be measured to move synchronously in the XYZ axes, and the adjustment accuracy is <1 μm. The irradiation component 110 and the light receiving component 120 are respectively arranged obliquely above the specimen to be measured, and they are rotationally symmetrically arranged with respect to the specimen to be measured. The irradiation component 110 can generate a polarized diffracted beam, and the irradiation optical path formed by the beam is directed towards the specimen to be measured, and an elliptically polarized small light spot is formed on the specimen to be measured. When the small light spot irradiates on the characteristic area of the specimen to be measured, the polarization state of the signal beam reflected from the specimen to be measured changes through interaction, thereby carrying the specimen information. Thus, when the light receiving component 120 receives the signal beam, the signal beam can be programmed into linearly polarized light and separated into effective irradiation light and diffracted stray light. Among them, the effective irradiation light is converged to the spectrometer, thereby obtaining the optical information (broad-spectrum amplitude information) of the specimen to be measured; the diffracted stray light is converged to the detector, thereby obtaining the height information of the specimen to be measured, facilitating subsequent calibration of the height of the specimen to be measured, and further increasing the measurement accuracy of the broad-spectrum amplitude information.

[0074] Figure 2 FIG. is a schematic structural diagram of an irradiation component provided by an embodiment of the present application. In combination with Figure 2 As shown, the irradiation component 110 includes: a beam generation component 210 and a beam adjustment component 310;

[0075] The beam generation component 210 includes: a light source 211, an ellipsoidal reflector 212, and a field stop 213;

[0076] The ellipsoidal reflector 212 is used to reflect the light emitted by the light source 211 and focus it on the small hole of the field stop 213 to generate a divergent beam; the light source 211 is a broad-spectrum light source; the light emitted by the broad-spectrum light source is in the ultraviolet to infrared band;

[0077] The beam adjustment component 310 is arranged in the optical path of the divergent beam and is used to adjust the irradiation light spot formed by the divergent beam on the specimen to be measured.

[0078] Specifically, to meet the requirement of a wide spectral range, the light source 211 adopted in the embodiments of the present application can emit light in the wavelength range of 185 nm - 2300 nm, and the light scatters in all directions. The light irradiated on the ellipsoidal mirror 212 will converge on the field stop 213. The field stop 213 in the embodiments of the present application is a small-hole stop. The ellipsoidal mirror 212 converges the light onto the small hole of the small-hole stop, and then the light diverges after passing through the small hole, forming a divergent light beam. The small-hole stop can be made by etching a small hole on a stainless-steel metal sheet. Generally, the small hole is a 40-μm circular hole. The beam adjustment assembly 310 is arranged in the optical path of the divergent light beam and is used to adjust the divergent light beam and the light spot formed by the divergent light beam on the sample to be measured. Generally, it is required that the light spot be as small as possible, the light intensity be as large as possible, and the light beam have a certain polarization state. It can be understood that the ellipsoidal mirror can reduce the light loss of the light source, thereby increasing the light intensity of the light converging on the field stop 213. In other embodiments, it may not be limited to the ellipsoidal mirror, and other devices can be used to achieve the functions of convergence and optical path adjustment, such as focusing lenses, mirrors, etc.

[0079] Figure 3 FIG. is a schematic diagram of the position setting of a first polarizer provided by an embodiment of the present application. Combining Figure 3 As shown, the beam adjustment assembly 310 includes: a first polarizer 311, a serrated aperture 312, and a first wide-spectrum achromatic lens 313;

[0080] The first polarizer 311 is arranged at the end of the optical path of the divergent light beam that is farthest from the field stop 213, and is used to adjust the polarization state of the divergent light beam to form a polarized light spot on the sample to be measured.

[0081] Specifically, in the beam adjustment assembly 310, the first polarizer 311 is arranged at the end that is farthest from the field stop 213. It can be a Glan-Taylor polarizing prism, whose function is to filter out the P light, so that the light beam incident on the sample to be measured is a linearly polarized light with only S light, and a polarized light spot is formed on the sample to be measured.

[0082] The serrated aperture 312 is arranged between the field stop 213 and the first polarizer 311 in the optical path of the divergent light beam, and is used to reduce the numerical aperture of the optical path of the divergent light beam and suppress Fresnel diffraction.

[0083] Specifically, since the serrated aperture 312 can limit the size of the irradiated geometric light spot, making the light intensity of the irradiated light spot greater, and its serrations can modulate the light intensity distribution, thereby suppressing Fresnel diffraction and reducing the size of the diffraction light spot. In the embodiment of the present application, a serrated aperture 312 is further provided in the beam adjustment assembly 310. The serrated aperture 312 is disposed between the field stop 213 and the first polarizer 311, which not only reduces the NA of the divergent beam optical path and reduces the size of the geometric light spot, but also modulates the light intensity distribution and limits the size of the diffraction light spot. At the same time, the serrations generate diffracted stray light for on-line in-situ calibration of the sample height position.

[0084] In addition, Figure 4 FIG. is a schematic structural diagram of a serrated aperture provided by an embodiment of the present application. As shown in combination with Figure 4 shown, the serrated aperture 312 is generally periodic fine teeth, and the fine teeth can be rectangular triangles, sine curves or other shapes. In the embodiment of the present application, the elliptical serrated aperture 312 ( Figure 4 a) can be used alone, and the rectangular serrated aperture 312 ( Figure 4 b) needs to be used in two perpendicular combinations. When the serrated aperture 312 is located in front of the optical lens of the irradiation optical path, as an elliptical serrated aperture 312 that can be used, its dimensions are: the X-direction aperture is 10 mm, triangular teeth, the bottom side length of the teeth is 0.3 mm, the tooth height is 4 mm, the Y-direction aperture is 6 mm, triangular teeth, the bottom side length of the teeth is 0.15 mm, and the tooth height is 2.5 mm.

[0085] The first wide-spectrum achromatic lens 313 is disposed between the field stop 213 and the first polarizer 311 in the optical path of the divergent beam, for reducing chromatic aberration and focusing light rays of different wavelengths at the same point.

[0086] Specifically, the irradiation optical path optical lens can use a (first) wide-spectrum achromatic lens, which is disposed between the field stop 213 and the first polarizer 311. Figure 5 FIG. is a schematic diagram of chromatic focal shift provided by an embodiment of the present application. As shown in combination with Figure 5 shown, through achromatic design, the first wide-spectrum achromatic lens 313 can achieve a chromatic focal shift of 638 um in the wavelength band of 185 nm - 2300 nm.

[0087] In addition, in the design of the beam adjustment assembly 310, the positional relationship between the serrated aperture 312 and the first wide-spectrum achromatic lens 313 can be selected and designed according to the optical path modulation requirements. For example, the serrated aperture 312 is located in front of the lens, in the lens or behind the lens. Since in the ellipsometry optical path, the beam irradiated on the sample is usually obliquely incident, the contour of the serrated aperture 312 can also change the ellipticity or the diameters of the two serrated apertures 312 according to the actual design.

[0088] Figure 6The structural schematic diagram of a light-receiving component provided by an embodiment of the present application. In combination with Figure 6 As shown, the light-receiving component 120 includes: a second wide-spectrum achromatic lens 220, a second polarizer 320, a separation component 420, a spectral detection module 520, and a calibration module 620;

[0089] The second wide-spectrum achromatic lens 220, the second polarizer 320, and the separation component 420 are sequentially arranged in the optical path of the signal beam along the propagation direction of the signal beam;

[0090] The separation component 420 is used to separate the diffracted stray light in the signal beam, control the diffracted stray light to be incident on the calibration module 620, and control the effective irradiation light in the signal beam to be incident on the spectral detection module 520.

[0091] Specifically, the second wide-spectrum achromatic lens 220 is symmetrically installed in the receiving optical path (the optical path of the signal beam) with respect to the first wide-spectrum achromatic lens 313, and the specifications of the second wide-spectrum achromatic lens 220 and the first wide-spectrum achromatic lens 313 are the same. The included angle between the irradiation optical path and the receiving optical path can be 90°, 120°, 130°, etc., which is specifically determined by the film material and thickness of the sample to be measured. The second wide-spectrum achromatic lens 220, the second polarizer 320, and the separation component 420 are sequentially arranged in the optical path of the signal beam along the propagation direction of the signal beam. The second polarizer 320 can also be a Glan-Taylor polarizing prism. After the signal beam passes through the second polarizer 320, it becomes linearly polarized light and continues to propagate towards the separation component 420. It can be understood that due to the existence of the serrated aperture 312, there are diffracted stray light and effective irradiation light in the signal beam. The separation component 420 can separate the diffracted stray light and the effective irradiation light in the signal beam according to the different propagation properties of different lights, and then direct the diffracted stray light to the calibration module 620 and the effective irradiation light to the spectral detection module 520.

[0092] As an implementation manner, regarding how to design the second polarizer 320, the second polarizer 320 is a rotatable Glan-Taylor polarizing prism and serves as a rotating analyzer.

[0093] Specifically, the second polarizer 320 is set as a rotatable Glan-Taylor polarizing prism. When measuring the sample to be measured, the measurement data can be increased by rotating the second polarizer 320.

[0094] As an implementation manner, regarding how to design the separation component 420, the separation component 420 includes a first part and a second part arranged in sequence along the circumferential direction. The first part is used to guide the effective irradiation light at the center of the signal beam to the spectral detection module 520 in a manner of reflection or transmission. The second part is located outside the first part and is used to guide the diffracted stray light outside the signal beam to the calibration module 620 in a manner of reflection or transmission. Further, the first part is used to guide the effective irradiation light at the center of the signal beam to the spectral detection module 520 in one of the ways of reflection and transmission, and the second part is used to guide the diffracted stray light outside the signal beam to the calibration module 620 in the other way of reflection and transmission. Among them, the effective irradiation light and / or the diffracted stray light transmitting through the separation component may be that the light beam passes through a transparent medium (such as a lens) or through a hole.

[0095] Specifically, according to the positional relationship between the effective irradiation light and the diffracted stray light in the signal beam and their respective covered irradiation ranges, the separation component 420 in the optical path is correspondingly provided with different structures at different positions, that is, a first part and a second part arranged in sequence along the circumferential direction, so as to enable the first part and the second part to respectively process the effective irradiation light at the center of the signal beam and the diffracted stray light outside the signal beam, separate the two, and guide them to the spectral detection module 520 and the calibration module 620 respectively.

[0096] Figure 7 This is a schematic structural diagram of a light receiving component with a light splitting component provided by an embodiment of the present application. Combining Figure 7 As shown, the light receiving component 120 further includes: a light splitting component 720; correspondingly, the spectral detection module 520 includes: a first spectrometer 521 and a second spectrometer 522; correspondingly, the separation component 420 includes: a first filtering component 421 and a second filtering component 422; correspondingly, the calibration module 620 includes: a first detector 621 and a second detector 622;

[0097] The first spectrometer 521 is a first band response wavelength spectrometer with a spectral resolution < 4 nm; the second spectrometer 522 is a second band response wavelength spectrometer with a spectral resolution < 8 nm; the wavelength in the first band is less than the wavelength in the second band;

[0098] The light splitting component 720 is arranged between the second polarizer 320 and the separation component 420 in the optical path of the signal beam, and is used to divide the signal beam into a second signal sub-beam and a first signal sub-beam;

[0099] The first signal sub-beam is incident on the first spectrometer 521;

[0100] The second signal sub-beam is directed towards the second spectrometer 522.

[0101] Specifically, the light source 211 provides light in the wavelength band of 185 nm - 2300 nm. Since the spectrum is relatively wide, in order to achieve wide-spectrum measurement and ensure the accuracy of the measurement, two spectrometers with different response wavelengths can be respectively set to obtain wide-spectrum amplitude information. The beam splitting component 720 can split the signal beam into two parts (the second signal sub-beam and the first signal sub-beam), one part is directed towards the first spectrometer 521, and the other part is directed towards the second spectrometer 522. As an example, in this application, the optical path is set such that the first signal sub-beam is directed towards the first spectrometer 521; the second signal sub-beam is directed towards the second spectrometer 522. The beam splitting component 720 can be a semi-transmissive and semi-reflective mirror, whose transmitted beam forms the first signal sub-beam, and whose reflected beam forms the second signal sub-beam. Among them, the first spectrometer 521 is a spectrometer with a response wavelength in the range of 185 nm - 1200 nm (the first wavelength band), and the spectral resolution is < 4 nm. Its function is to collect and analyze the spectral light intensity information in the 185 nm - 1200 nm wavelength band in different rotation angle states of the second polarizer 320. The second spectrometer 522 is a spectrometer with a response wavelength in the range of 1200 nm - 2300 nm (the second wavelength band), and the spectral resolution is < 8 nm. Its function is to collect and analyze the spectral light intensity information in the 1200 nm - 2500 nm wavelength band in different rotation angle states of the second polarizer 320. In addition, since the achromatic lens cannot completely eliminate chromatic aberration, there is chromatic aberration in the illumination spot, and the focal points of the illumination spots in the two wavelength bands of 185 - 1200 nm and 1200 nm - 2300 nm are inconsistent. The spot position information received by the first detector 621 and the second detector 622 can be used to respectively calibrate the focal points of the two wavelength bands, improving the measurement accuracy. The sample height accuracy can reach 0.2 um.

[0102] The first filtering component 421 is used to filter the first signal sub-beam, and direct the first diffracted stray light in the first signal sub-beam towards the first detector 621; the wavelength band of the first diffracted stray light is the first wavelength band;

[0103] The second filtering component 422 is used to filter the second signal sub-beam, and direct the second diffracted stray light in the second signal sub-beam towards the second detector 622; the wavelength band of the second diffracted stray light is the second wavelength band.

[0104] Specifically, the first spectrometer 521 can analyze the spectral light intensity information in the wavelength band of 185 nm - 1200 nm. However, since the diffracted stray light (the first diffracted stray light) in the wavelength band of 185 nm - 1200 nm (the first wavelength band) in the first signal sub-beam will affect the analysis result of the first spectrometer 521, a corresponding first filtering component 421 needs to be set to filter it, and the filtered diffracted stray light in the wavelength band of 185 nm - 1200 nm is projected onto the first detector 621. Similarly, in order to filter the diffracted stray light (the second diffracted stray light) in the wavelength band of 1200 nm - 2300 nm in the second signal sub-beam, the second filtering component 422 is set in the embodiment of the present application to filter it, and the filtered diffracted stray light in the wavelength band of 1200 nm - 2300 nm (the second wavelength band) is projected onto the second detector 622.

[0105] As an implementation manner, regarding how to design the beam splitting component 720, the above-mentioned beam splitting component 720 is a dot beam splitter, which is composed of a UV-grade fused silica substrate and an array of enhanced aluminum films uniformly deposited on the fused silica substrate;

[0106] The incident angle of the signal beam on the beam splitting component 720 is 45°.

[0107] Specifically, the beam splitting component 720 in the embodiment of the present application is a dot beam splitter, which is formed by depositing an array of enhanced aluminum films uniformly on a UV-grade fused silica substrate. In order to achieve uniform beam splitting, the signal beam can be incident on the beam splitting component 720 at an incident angle of 45°. The beam splitting component 720 reflects the light incident on the enhanced aluminum film array to form a second signal sub-beam and projects it onto the second spectrometer 522; the light not incident on the enhanced aluminum film array is transmitted to form a first signal sub-beam and projects it onto the first spectrometer 521. In other embodiments, it may not be limited to the dot beam splitter, and other devices can be used to achieve the beam splitting function, such as a semi-transmissive and semi-reflective mirror, etc.

[0108] As an implementation manner, regarding how to design the first filtering component 421 and the second filtering component 422, the above-mentioned first filtering component 421 includes a third part and a fourth part arranged in sequence along the circumferential direction. The third part is used to guide the effective irradiation light at the center of the first signal sub-beam to the first spectrometer 521 in a reflective or transmissive manner, and the fourth part is located outside the third part and is used to guide the diffracted stray light outside the first signal sub-beam to the first detector 621 in a reflective or transmissive manner; further, the third part is used to guide the effective irradiation light at the center of the first signal sub-beam to the first spectrometer 521 in one of reflection and transmission, and the fourth part is used to guide the diffracted stray light outside the first signal sub-beam to the first detector 621 in the other of reflection and transmission.

[0109] The second filtering component 422 includes a fifth part and a sixth part arranged in sequence along the circumferential direction. The fifth part is used to guide the effective irradiation light at the center of the second signal sub-beam to the second spectrometer 522 in a manner of reflection or transmission. The sixth part is located outside the fifth part and is used to guide the diffracted stray light outside the second signal sub-beam to the second detector 622 in a manner of reflection or transmission. Further, the fifth part is used to guide the effective irradiation light at the center of the second signal sub-beam to the second spectrometer 522 in one of the ways of reflection and transmission, and the sixth part is located outside the fifth part and is used to guide the diffracted stray light outside the second signal sub-beam to the second detector 622 in the other way of reflection and transmission.

[0110] Specifically, according to the positional relationship between the effective irradiation light and the diffracted stray light in the first band of the first signal sub-beam and their respective covered irradiation ranges, different structures are set at different positions of the first filtering component 421 in the optical path, that is, a third part and a fourth part arranged in sequence along the circumferential direction, so that the third part and the fourth part respectively process the effective irradiation light in the first band at the center of the first signal sub-beam and the diffracted stray light in the first band outside the first signal sub-beam, separate the two, and guide them to the first spectrometer 521 and the first detector 621 respectively. Similarly, based on the different positions of the diffracted stray light in the first band and the second band and their respective covered irradiation ranges, different structures are set at different positions of the second filtering component 422 in the optical path, that is, a fifth part and a sixth part arranged in sequence along the circumferential direction, so that the fifth part and the sixth part respectively process the effective irradiation light in the second band at the center of the second signal sub-beam and the diffracted stray light in the second band outside the second signal sub-beam, separate the two, and guide them to the second spectrometer 522 and the second detector 622 respectively.

[0111] As an implementation manner, regarding how to design the first filtering component 421 and the second filtering component 422, the first filtering component 421 is composed of a first small hole diaphragm or a first reflector. When the first filtering component is the first small hole diaphragm, the third part is the small hole, and the fourth part is an ultraviolet-enhanced aluminum film plated on the quartz substrate outside the small hole. Further, the size of the small hole is 60um * 120um. When the first filtering component is the first reflector, the third part is a first reflective metal film plated in the middle, and the fourth part is a lens outside the first reflective metal film. Further, the size of the first reflective metal film is 60um * 120um.

[0112] Since the wavelength ranges from ultraviolet to infrared and there are relatively few types of available glass materials, the achromatic lens cannot completely eliminate chromatic aberration. Therefore, the spot sizes of the light spots incident on the first filter component and the second filter component are different. Thus, the sizes of the central small holes of the first filter component and the second filter component need to be determined based on the actual effective irradiation light size and the spacing distance between the effective irradiation light and the diffracted stray light, so as to separate the effective irradiation light and the diffracted stray light in the signal light beam.

[0113] The second filter component 422 is composed of a second small hole diaphragm or a second mirror; when the second filter component is the second small hole diaphragm, the fifth part is a small hole, and the sixth part is an infrared-enhanced silver film plated on the quartz substrate outside the small hole. Further, the size of the small hole is 80um * 160um; when the second filter component is the second mirror, the fifth part is a second reflective metal film plated in the middle, and the sixth part is a lens outside the second reflective metal film. Further, the size of the second reflective metal film is 80um * 160um..

[0114] Figure 8 Schematic diagrams of small hole diaphragms with two different processes provided by the embodiments of the present application. Combining Figure 8 As shown, the first filter component 421 provided in the embodiment of the present application corresponds to the first detector 621 and the first spectrometer 521. The first filter component 421 can be a first small hole diaphragm. For example, Figure 8 a, in order to filter the diffracted stray light in the 185nm - 1200nm wavelength band, the first small hole diaphragm is set as a mirror structure with an ultraviolet-enhanced aluminum film plated on a quartz substrate. Then, based on the different distances between the diffracted stray light in the 185nm - 1200nm wavelength band and the effective irradiation light, and the different spot sizes of the effective irradiation light, a 60um * 120um small hole is etched in the center of the mirror structure on the ultraviolet-enhanced aluminum film. After the first transmitted light is incident on the first small hole diaphragm, its transmitted light filters out the diffracted stray light in the 185nm - 1200nm wavelength band. Therefore, it is incident on the first spectrometer 521, and its reflected light is the diffracted stray light in the 185nm - 1200nm wavelength band. Therefore, it is incident on the first detector 621. As another setting of the first filter component 421, the first filter component 421 can also be a mirror structure (first mirror) with a 60um * 120um small hole in the middle plated with a reflective metal film (first reflective metal film) and the edge not coated, as Figure 8b. At this time, the transmitted light is the diffracted stray light in the wavelength band of 185 nm - 1200 nm, and its reflected light filters out the diffracted stray light in the wavelength band of 185 nm - 1200 nm, so it is directed towards the first spectrometer 521. Similarly, the second filtering component 422 can also be composed of a second small aperture diaphragm or a second reflecting mirror. However, the distance between the diffracted stray light with a wavelength of 185 nm - 1200 nm and the effective irradiation light is different from the distance between the diffracted stray light with a wavelength of 1200 nm - 2300 nm and the effective irradiation light, and the spot size of the effective irradiation light is also different. For this reason, the aperture size of the second small aperture diaphragm is 80 um * 160 um, and an infrared-enhanced silver film is plated on the quartz substrate outside the aperture. The second reflecting mirror is plated with a second reflecting metal film in the middle, and the size of the second reflecting metal film is 80 um * 160 um.

[0115] Figure 9 This is a schematic diagram of an irradiation spot provided by an embodiment of the present application. Combining Figure 9 As shown, a is the irradiation spot on the sample to be measured in the wavelength band of 185 nm - 1200 nm, b is the irradiation spot on the first small aperture diaphragm in the wavelength band of 185 nm - 1200 nm, c is the irradiation spot on the sample to be measured in the wavelength band of 1200 nm - 2300 nm, and d is the irradiation spot on the second small aperture diaphragm in the wavelength band of 1200 nm - 2300 nm.

[0116] In addition, both the first small aperture diaphragm and the second small aperture diaphragm are installed obliquely at an angle of 45° relative to the light beam.

[0117] Figure 10 This is a schematic diagram of the optical path of an ellipsometry system provided by an embodiment of the present application. Combining Figure 10 As shown, the calibration module 620 includes: a first filter 821 and a first condenser 921 correspondingly arranged with the first detector 621, and a second filter 822 and a second condenser 922 correspondingly arranged with the second detector 622;

[0118] The first filter 821, the first condenser 921 and the first detector 621 are sequentially arranged in the optical path of the first diffracted stray light along the propagation direction of the first diffracted stray light;

[0119] The first filter 821 is a narrowband filter in the third wavelength band, which is used to limit the wavelength of the first diffracted stray light; the third wavelength band is within the first wavelength band;

[0120] The first condenser 921 is used to converge the first diffracted stray light with the limited wavelength onto the first detector 621;

[0121] The second filter 822, the second condenser lens 922, and the second detector 622 are sequentially arranged in the optical path of the second diffracted stray light along the propagation direction of the second diffracted stray light;

[0122] The second filter 822 is a narrow-band filter in the fourth band, and is used to limit the wavelength of the second diffracted stray light; the fourth band is within the second band;

[0123] The second condenser lens 922 is used to converge the second diffracted stray light with the limited wavelength onto the second detector 622.

[0124] Specifically, the first filter 821 and the first condenser lens 921 are used corresponding to the first detector 621. Since the light beam incident on the first detector 621 is the diffracted stray light in the 185 nm - 1200 nm band, in order to limit the wavelength of the light intensity converged onto the first detector 621 by the first condenser lens 921, the first filter 821 can be set as a narrow-band filter of 550 ± 50 nm (the third band), thereby reducing the chromatic aberration influence of the condenser lens and improving the accuracy of the height measurement of the sample to be measured. The first condenser lens 921 is a double-glued lens, and the materials are calcium fluoride and fused quartz, and are used to converge the diffracted stray light in the 550 ± 50 nm band after filtering onto the first detector 621, and then the first detector 621 obtains the height information of the sample to be measured. Similarly, the second filter 822 and the second condenser lens 922 are used corresponding to the second detector 622. Since the light beam incident on the second detector 622 is the diffracted stray light in the 1200 nm - 2300 nm band, in order to limit the wavelength of the light intensity converged onto the second detector 622 by the second condenser lens 922, the second filter 822 can be set as a narrow-band filter of 2000 ± 100 nm (the fourth band). The second condenser lens 922 is the same as the first condenser lens 921, and is a double-glued lens, and is used to converge the diffracted stray light in the 2000 ± 100 nm band after filtering onto the second detector 622, and then the second detector 622 obtains the height information of the sample to be measured.

[0125] In summary, an ellipsometry system and a measurement method provided by the present application. The system includes an illumination component and a light receiving component. The illumination component is disposed obliquely above the first plane side of the sample to be measured, and is used to generate a polarized diffracted beam and obliquely irradiate the polarized diffracted beam onto the sample to be measured. The sample to be measured is used to reflect the polarized diffracted beam and generate a signal beam. The light receiving component is disposed obliquely above the second plane side of the sample to be measured, and is used to receive the signal beam and separate the effective illumination light and diffracted stray light in the signal beam. The effective illumination light and diffracted stray light are respectively used by the light receiving component to determine the optical information and height information of the sample to be measured. In this way, through the cooperation of the illumination component and the light receiving component, the effective illumination light and diffracted stray light can be generated and separated, and then used to measure the optical information and height information of the sample to be measured respectively, ensuring the measurement accuracy of the ellipsometry system.

[0126] Figure 11 It is a flowchart of a measurement method for an ellipsometry system provided by an embodiment of the present application. In combination with Figure 11 As shown, in a measurement method for an ellipsometry system provided by an embodiment of the present application, the system includes an illumination component and a light receiving component. The corresponding measurement method includes:

[0127] S1101: Configure the illumination component so that the polarized diffracted beam generated by the illumination component can irradiate on the sample to be measured and generate a signal beam.

[0128] In practical applications, a broadband light source (in the 185nm - 2300nm band) and a serrated aperture are configured in the illumination component. Figure 12 It is a PSF cross-sectional view with and without a serrated aperture at different wavelengths provided by an embodiment of the present application. In combination with Figure 12 As shown, a is the PSF cross-sectional view without a serrated aperture in the 185nm - 1200nm band, b is the PSF cross-sectional view with a serrated aperture in the 185nm - 1200nm band, c is the PSF cross-sectional view without a serrated aperture in the 1200nm - 2300nm band, and d is the PSF cross-sectional view with a serrated aperture in the 1200 - 2300nm band. It can be seen that whether in the 185nm - 1200nm band or the 1200 - 2300nm band, for the illumination component configured with a serrated aperture, the size of the illumination spot is always smaller than that of the illumination spot without a serrated aperture. In this way, by configuring the illumination component, the formed illumination light path obliquely irradiates on the sample to be measured, and an elliptically polarized small spot with a known polarization state can be generated on the sample to be measured. The spot irradiates on the characteristic area of the sample to be measured, and the interaction causes the polarization state of the reflected light to change, thereby generating a signal beam carrying the sample information of the sample to be measured, and shooting the first reflected light towards the light receiving component.

[0129] S1102: Set the light-receiving component on the optical path of the signal beam so that the light-receiving component can receive the signal beam and separate the effective irradiation light and diffracted stray light in the signal beam.

[0130] In practical applications, since the distances between diffracted stray lights of different wavelengths and the effective irradiation light are different, and the spot sizes of the effective irradiation light are also different, the diffracted stray light and the effective irradiation light can be separated by wavelength in two segments (185 nm - 1200 nm and 1200 - 2300 nm). The separation component can be a small aperture diaphragm of a specific size or a mirror. When the signal beam irradiates on the separation component, the separation component can separate the effective irradiation light and the diffracted stray light in the signal beam.

[0131] S1103: Use the light-receiving component to determine the optical information of the sample to be measured according to the effective irradiation light, and determine the height information of the sample to be measured according to the diffracted stray light.

[0132] In practical applications, a spectral detection module and a calibration module are configured in the light-receiving component. The effective irradiation light and the diffracted stray light separated from the signal beam are respectively directed to the spectral detection module and the calibration module. Among them, the spectral detection module can obtain the wide-spectrum amplitude information of the sample to be measured according to the effective irradiation light, and the calibration module can obtain the height information of the sample to be measured according to the diffracted stray light.

[0133] Figure 13 This is a schematic diagram showing the relationship between the height of the sample and the centroid of the light spot provided by the embodiment of the present application. Combined with Figure 13 As shown, the diffracted light generated by the fine teeth of the serrated aperture is reflected into the converging mirror, and the stray light at the sample to be measured is imaged onto the detector, thereby obtaining the position information of the diffracted stray light. When the r height of the sample to be measured is different, the position of the diffracted stray light on the detector is different, thus realizing the in-situ focusing function. Since the positions of the irradiation component and the light-receiving component are relatively fixed, and the ellipsometry system should ensure that the surface of the sample to be measured is at the focal position of the objective lens during measurement. Therefore, when the focal position of the known irradiation optical path is known, the height of the sample to be measured determined by the calibration module can be used to adjust the height of the sample to be measured by using the sample stage so that the surface of the sample to be measured is at the focal position of the objective lens, and then more accurate wide-spectrum amplitude information of the sample to be measured can be obtained.

[0134] In summary, based on an ellipsometry system provided by the present application, the present application provides a measurement method for an ellipsometry system, including: First, configure an illumination component so that the polarized diffracted light beam generated by the illumination component can irradiate a sample to be measured and generate a signal light beam. Then, arrange a light receiving component on the optical path of the signal light beam so that the light receiving component can receive the signal light beam and separate the effective illumination light and diffracted stray light in the signal light beam. Finally, use the light receiving component to determine the optical information of the sample to be measured according to the effective illumination light and determine the height information of the sample to be measured according to the diffracted stray light. In this way, through the cooperation of the illumination component and the light receiving component, the effective illumination light and the diffracted stray light can be generated and separated, and then used to measure the optical information and height information of the sample to be measured respectively, ensuring the measurement accuracy of the ellipsometry system.

[0135] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An ellipsometric measurement system, characterized in that: include: Illuminating components and light receiving components; The irradiation assembly is disposed at a first obliquely upper portion of a first plane side of the sample to be tested, and is used to generate a polarized diffraction light beam and obliquely irradiate the polarized diffraction light beam toward the sample to be tested; The sample to be tested is used to reflect the polarized diffraction light beam and generate a signal light beam; The light receiving component is arranged at the second obliquely upper side of the first plane side of the sample to be tested, and is used to receive the signal light beam and separate the effective illumination light and the diffracted stray light in the signal light beam; the effective illumination light and the diffracted stray light are respectively used by the light receiving component to determine the optical information and height information of the sample to be tested.

2. The ellipsometric measurement system according to claim 1, characterized in that: The irradiation assembly includes: a light beam generating assembly and a light beam adjusting assembly; The light beam generating assembly comprises: a light source, an ellipsoidal reflector and a field stop; The ellipsoid reflector is used to reflect the light emitted by the light source and focus it on the small hole of the field aperture to generate a divergent light beam; the light source is a wide-spectrum light source; the light emitted by the wide-spectrum light source is in the ultraviolet to infrared band; The beam adjustment component is arranged in the optical path of the divergent light beam, and is used to adjust the irradiation spot formed by the divergent light beam on the sample to be measured.

3. The ellipsometric measurement system according to claim 2, characterized in that: The beam adjustment assembly includes: a first polarizer; The first polarizer is disposed at an end of the light path of the divergent light beam farthest from the field stop, and is used to adjust the polarization state of the divergent light beam to form a polarized light spot on the sample to be measured.

4. The ellipsometric measurement system according to claim 3, characterized in that: The beam adjustment assembly includes: a sawtooth diaphragm; The sawtooth diaphragm is arranged between the field diaphragm and the first polarizer in the optical path of the divergent light beam, and is used to reduce the numerical aperture of the optical path of the divergent light beam and suppress Fresnel diffraction.

5. The ellipsometric measurement system according to claim 4, characterized in that: The beam adjustment assembly includes: a first wide spectrum achromatic lens; The first wide spectrum achromatic lens is disposed between the field stop and the first polarizer in the optical path of the divergent light beam.

6. The ellipsometric measurement system according to claim 1, characterized in that: The light receiving component includes: a second wide spectrum achromatic lens, a second polarizer, a separation component, a spectrum detection module and a calibration module; The second wide spectrum achromatic lens, the second polarizer and the separation component are sequentially arranged in the optical path of the signal light beam along the propagation direction of the signal light beam; The separation component is used to separate the diffracted stray light in the signal light beam, and control the diffracted stray light to be directed toward the calibration module, and control the effective illumination light in the signal light beam to be directed toward the spectrum detection module.

7. The ellipsometric measurement system according to claim 6, characterized in that: The second polarizer is a rotatable Glan-Taylor polarizing prism, which acts as a rotating analyzer.

8. The ellipsometric measurement system according to claim 6, characterized in that: The separation component includes a first part and a second part which are arranged in sequence along the circumferential direction, the first part is used to guide the effective illumination light at the center of the signal light beam to the spectral detection module by reflection or transmission, and the second part is located outside the first part, and is used to guide the diffracted stray light outside the signal light beam to the calibration module by reflection or transmission.

9. The ellipsometric measurement system according to claim 6, characterized in that: The light receiving component also includes: a spectroscopic component; the spectrum detection module includes: a first spectrometer and a second spectrometer; the first spectrometer response is a first band response wavelength spectrometer, and the spectral resolution is less than 4nm; the second spectrometer is a second band response wavelength spectrometer, and the spectral resolution is less than 8nm; the wavelength in the first band is smaller than the wavelength in the second band; The beam splitting component is disposed between the second polarizer and the separation component in the optical path of the signal beam, and is used to split the signal beam into the first signal sub-beam and the second signal sub-beam; The first signal sub-beam is directed toward the first spectrometer; The second signal sub-beam is directed toward the second spectrometer.

10. The ellipsometric measurement system according to claim 9, characterized in that: The beam splitter component is a dot beam splitter, which is composed of a UV grade fused silica substrate and a reinforced aluminum film dot matrix evenly distributed on the fused silica substrate; The incident angle of the signal light beam on the beam splitter is 45°.

11. The ellipsometric measurement system according to claim 9, characterized in that: The separation component includes: a first filter component and a second filter component; the calibration module includes: a first detector and a second detector; The first filter component is used to filter the first signal sub-beam, and direct the first diffracted stray light in the first signal sub-beam toward the first detector; the wavelength band of the first diffracted stray light is the first wavelength band; The second filter component is used for filtering the second signal sub-beam, and directing the second diffracted stray light in the second signal sub-beam toward the second detector; the wavelength band of the second diffracted stray light is the second wavelength band.

12. The ellipsometric measurement system according to claim 11, characterized in that: The first filter assembly comprises a third part and a fourth part which are sequentially arranged along the circumferential direction, the third part is used to guide the effective illumination light at the center of the first signal sub-beam to the first spectrometer by reflection or transmission, and the fourth part is located outside the third part, and is used to guide the diffracted stray light outside the first signal sub-beam to the first detector by reflection or transmission; The second filtering assembly includes a fifth part and a sixth part which are arranged in sequence along the circumferential direction, the fifth part is used to guide the effective illumination light in the center of the second signal sub-beam to the second spectrometer by reflection or transmission, and the sixth part is located outside the fifth part, and is used to guide the diffracted stray light outside the second signal sub-beam to the second detector by reflection or transmission.

13. The ellipsometric measurement system according to claim 12, characterized in that: The first filter component is composed of a first pinhole aperture or a first reflector; when the first filter component is the first pinhole aperture, the third part is a pinhole, and the fourth part is a UV-enhanced aluminum film coated on a quartz substrate outside the pinhole, and the size of the pinhole is 60um*120um; when the first filter component is the first reflector, the third part is a first reflective metal film coated in the middle, and the fourth part is a lens outside the first reflective metal film, and the size of the first reflective metal film is 60um*120um; The second filter component is composed of a second pinhole aperture or a second reflector; when the second filter component is the second pinhole aperture, the fifth part is the pinhole, and the sixth part is the infrared enhanced silver film coated on the quartz substrate outside the pinhole, and the size of the pinhole is 80um*160um; when the second filter component is the second reflector, the fifth part is the second reflective metal film coated in the middle, and the sixth part is the lens outside the second reflective metal film, and the size of the second reflective metal film is 80um*160um.

14. The ellipsometric measurement system according to claim 11, characterized in that: The calibration module comprises: a first filter and a first focusing mirror arranged corresponding to the first detector, and a second filter and a second focusing mirror arranged corresponding to the second detector; The first filter, the first converging mirror and the first detector are sequentially arranged in the optical path of the first diffracted stray light along the propagation direction of the first diffracted stray light; The first filter is a narrow-band filter of a third wavelength band, used for limiting the wavelength of the first diffraction stray light; the third wavelength band is within the first wavelength band; The first converging mirror is used to converge the first diffracted stray light after limiting the wavelength onto the first detector; The second filter, the second converging mirror and the second detector are sequentially arranged in the optical path of the second diffracted stray light along the propagation direction of the second diffracted stray light; The second optical filter is a narrow-band optical filter of a fourth wavelength band, and is used to limit the wavelength of the second diffracted stray light; the fourth wavelength band is within the second wavelength band; The second converging mirror is used to converge the second diffracted stray light after limiting the wavelength onto the second detector.

15. A measurement method for an ellipsometric measurement system, characterized in that: The system includes an irradiation component and a light receiving component, and the measurement method includes: Configuring the irradiation component so that the polarized diffraction light beam generated by the irradiation component can be irradiated on the sample to be tested and generate a signal light beam; The light receiving component is arranged on the optical path of the signal light beam, so that the light receiving component can receive the signal light beam and separate the effective illumination light and the diffracted stray light in the signal light beam; The light collecting component is used to determine the optical information of the sample to be measured according to the effective irradiated light, and the height information of the sample to be measured is determined according to the diffracted stray light.

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