Ellipsometry apparatus and method of measurement

Abstract

The application provides an ellipsometry device and a measuring method thereof. The device comprises left-right symmetrical parabolic adjusting mirrors. A light beam is incident on a first eccentric lens through a first mirror. A control module controls the eccentricity of the first and second eccentric lenses to make the light beam incident on the adjusting mirrors at a preset angle, then reflected to the adjusting mirrors after passing through a hole, incident on a second eccentric lens, incident on a second mirror, and analyzed by a light detector to obtain sample parameters. A polarizer and an analyzer make the light beam polarized light. The application uses parabolic mirrors as the mirror surface of the sample. The light beam can be incident on the surface of the sample from different positions at different incident angles, and different materials can be measured flexibly. Meanwhile, the automatic control of the eccentricity of the eccentric lenses is combined to realize simple and accurate adjustment of the incident angle. In addition, the automatic phase deflection compensation of the light beam by a compensator simplifies the calculation process of the ellipsometric parameters.

Description

Technical Field

[0001] This invention belongs to the field of optical equipment design, and in particular relates to an elliptic polarization measurement device and its measurement method. Background Technology

[0002] Light waves are essentially electromagnetic waves, a type of vector wave, and therefore possess polarization properties. The polarization of light is usually represented by the change of the electric field vector E at a point over time. Based on the polarization properties, light can be classified into linearly polarized light, circularly polarized light, elliptically polarized light, and partially polarized light. An ellipsometer, or simply ellipsometer, is a device that uses a polarizer to generate linearly polarized light incident on a sample, and measures the optical constants and film thickness information of the sample based on the change in the polarization characteristics of the reflected light. The ellipsometer determines the sample parameters by measuring the ratio of the reflectivity Rp parallel to the incident plane to the reflectivity Rs perpendicular to the incident plane.

[0003] Traditional ellipsometers incident at a fixed angle to the sample surface, typically the Brewster angle of the sample. This is because the range of variation in Rp (the angle of incidence) is relatively large near the Brewster angle, thus increasing the ellipsometer's measurement sensitivity. However, when the sample changes, the Brewster angle varies due to differences in the material's optical constants. If the ellipsometer is not used at the Brewster angle, the sensitivity of the measurement will decrease in the applicable scenario. Therefore, there is an urgent need for a ellipsometer with a continuously variable incident angle to meet application requirements.

[0004] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating the understanding of those skilled in the art. It should not be assumed that the above technical solutions are known to those skilled in the art simply because these solutions have been described in the background section of this application. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide an elliptic polarization measurement device and its measurement method to solve the problem of low sensitivity of ellipsometers for measuring different samples in the prior art.

[0006] To achieve the above objectives, the present invention provides an elliptic polarization measurement device, the device comprising: a light source, a first reflecting mirror, a control module, a first eccentric lens, an adjusting reflecting mirror, a second eccentric lens, a second reflecting mirror, and a photodetector; The adjustable reflector is a parabolic reflector that is symmetrical from left to right. A hole is provided at the bottom of the adjustable reflector. The hole is located on the axis of symmetry of the adjustable reflector, and the sample material is exposed below the hole. The light beam emitted by the light source is reflected by the first reflecting mirror and then enters the first eccentric lens. The control module controls the position offset and offset direction of the first eccentric lens, so that the light beam passes through the first eccentric lens and enters the adjusting reflecting mirror, and after the first reflection, enters the aperture of the adjusting reflecting mirror at a preset angle. After the light beam enters the surface of the sample material exposed by the aperture, it is reflected a second time to the adjusting reflecting mirror. After the light beam is reflected a third time from the adjusting reflecting mirror, it enters the second eccentric lens. The position of the third reflection on the adjusting reflecting mirror is symmetrical to the position of the first reflection along the axis of symmetry of the adjusting reflecting mirror. The control module controls the position offset and offset direction of the second eccentric lens, so that the light beam passes through the second eccentric lens and enters the second reflecting mirror, and is reflected to the photodetector. The photodetector is used to analyze the properties of the incident light beam to obtain the parameters of the sample material. A polarizer is disposed between the light source and the first reflector, the polarizer being used to make the light beam generated by the light source polarized light with a preset polarization state; and / or an analyzer is disposed between the second reflector and the photodetector, the analyzer being used to restrict only the polarized light with the preset polarization state from passing through the light beam emitted from the second reflector.

[0007] Optionally, when the light beam enters the aperture of the adjusting mirror at a preset angle after the first reflection, the Brewster angle of the sample material is α, and the range of the preset angle is α ± 3°.

[0008] Optionally, light beams incident on the aperture of the adjusting mirror at different preset angles are all incident on the adjusting mirror in mutually parallel directions.

[0009] Optionally, the first reflector and / or the second reflector are motor-controlled angle-adjustable reflectors or MEMS reflector structures.

[0010] Optionally, the photodetector is a spectrometer.

[0011] Optionally, a compensator may be provided between the polarizer and the first reflector; and / or a compensator may be provided between the analyzer and the second reflector.

[0012] The present invention also provides a measurement method for an ellipsometric measuring device, wherein the measurement method uses any one of the ellipsometric measuring devices described above, and the measurement method includes: The light source emits a beam of light; The first reflector reflects the light beam, causing the light beam to enter the first eccentric lens. The control module controls the position offset and offset direction of the first eccentric lens, so that the light beam passes through the first eccentric lens and enters the adjustment reflector, and after the first reflection, enters the hole of the adjustment reflector at a preset angle. After the light beam is incident on the surface of the sample material exposed by the hole, it is reflected a second time onto the adjusting mirror. After being reflected a third time from the adjusting mirror, the light beam is incident on the second eccentric lens. The position of the third reflection of the light beam on the adjusting mirror is symmetrical to the position of the first reflection along the axis of symmetry of the adjusting mirror. The control module controls the position offset and offset direction of the second eccentric lens, so that the light beam passes through the second eccentric lens, enters the second reflecting mirror, and is reflected to the photodetector. The photodetector is used to analyze the properties of the incident light beam in order to obtain the parameters of the sample material; Before the light beam enters the first reflector, a polarizer is located between the light source and the first reflector, so that the light beam generated by the light source becomes polarized light with a preset polarization state; and / or before the light beam enters the photodetector, an analyzer is located between the second reflector and the photodetector, restricting only polarized light with a preset polarization state from passing through the light beam emitted from the second reflector.

[0013] Optionally, the photodetector processes the received beam energy and the beam energy emitted by the light source to obtain the angle of the polarizer and / or the angle of the analyzer, thereby obtaining the ellipsoid parameters, and correspondingly obtaining the optical constants and film thickness of the sample material.

[0014] Optionally, the light beam is incident from the polarizer to the first mirror, and a compensator is disposed between the polarizer and the first mirror to compensate for the phase delay caused by the sample material; and / or the light beam is incident from the second mirror to the analyzer, and a compensator is disposed between the analyzer and the second mirror to compensate for the phase delay caused by the sample material. The photodetector processes the received beam energy and the phase delay compensated by the compensator to calculate the optical constants and film thickness of the sample material.

[0015] Optionally, when the light beam enters the aperture of the adjusting mirror at a preset angle after the first reflection, the Brewster angle of the sample material is α, and the range of the preset angle is α ± 3°.

[0016] As described above, the elliptic polarization measuring device and method of the present invention have the following beneficial effects: This invention utilizes a parabolic surface as a reflective mirror for the sample, allowing the sample surface to be incident from different positions at different incident angles, thus enabling flexible measurement of different materials. This invention, combined with the automatic offset control of the eccentric lens, enables simple and precise adjustment of the incident angle; This invention utilizes a compensator to automatically compensate for the phase deflection of the beam, simplifying the calculation process of ellipticity parameters. Attached Figure Description

[0017] Figure 1 The diagram shown is a structural schematic of the elliptic polarization measuring device in Embodiment 1 of the present invention.

[0018] Figure 2 The diagram shown is a schematic representation of an optional example of an elliptic polarization measurement device according to Embodiment 1 of the present invention, which includes a compensator.

[0019] Figure 3 The diagram shown is a schematic representation of an optional example of an elliptic polarization measurement device according to Embodiment 1 of the present invention, which includes two compensators.

[0020] Component designation explanation 101. Light source; 102. Polarizer; 103. First reflector; 104. Control module; 105. First eccentric lens; 106. Adjustable reflector; 107. Sample material; 109. Second eccentric lens; 110. Second reflector; 111. Analyzer; 112. Photodetector; 113. Compensator. Detailed Implementation

[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0022] In the detailed description of embodiments of the present invention, for ease of explanation, the schematic diagrams illustrating the device structure may be partially enlarged without adhering to the general scale, and the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. Furthermore, in actual manufacturing, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0023] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the accompanying drawings for devices in use or operation.

[0024] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0025] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex. Example 1:

[0026] like Figure 1 As shown, the present invention provides an elliptic polarization measurement device, the device comprising: a light source 101, a first reflector 103, a control module 104, a first eccentric lens 105, an adjusting reflector 106, a second eccentric lens 109, a second reflector 110, and a photodetector 112. The adjustable reflector 106 is a parabolic reflector that is symmetrical from left to right. A hole is provided at the bottom of the adjustable reflector 106. The hole is located on the axis of symmetry of the adjustable reflector 106, and the sample material 107 is exposed below the hole. The light beam emitted by the light source 101 is reflected by the first reflector 103 and then enters the first eccentric lens 105. The control module 104 controls the position offset and offset direction of the first eccentric lens 105, so that the light beam passes through the first eccentric lens 105 and enters the adjusting reflector 106, and after the first reflection, enters the aperture of the adjusting reflector 106 at a preset angle. After the light beam enters the surface of the sample material 107 exposed by the aperture, it is reflected a second time onto the adjusting reflector 106. The light beam then exits the adjusting reflector... After the third reflection by mirror 106, the light beam enters the second eccentric lens 109. The position of the third reflection on the adjusting mirror 106 is symmetrical to the position of the first reflection along the axis of symmetry of the adjusting mirror 106. The control module 104 controls the position offset and offset direction of the second eccentric lens 109, so that the light beam passes through the second eccentric lens 109 and enters the second mirror 110, and is reflected to the photodetector 112. The photodetector 112 is used to analyze the properties of the incident light beam to obtain the parameters of the sample material 107. A polarizer 102 is disposed between the light source 101 and the first reflector 103, the polarizer 102 being used to make the light beam generated by the light source 101 polarized light with a preset polarization state; and / or an analyzer 111 is disposed between the second reflector 110 and the photodetector 112, the analyzer 111 being used to restrict only the polarized light with the preset polarization state from passing through the light beam emitted from the second reflector 110.

[0027] Specifically, in the figure, 1, 2, and 3 are three beams that are incident on the first eccentric lens 105 at different angles on the first reflector 103. Among them, beam 2 passes through the optical center of the first eccentric lens 105, so the angle of beam 2 remains unchanged after passing through the first eccentric lens 105. The first eccentric lens 105 is controlled by the control module 104 to offset the amount and direction of offset, so that beams 1 and 2 can be parallel to the beam direction of beam 2 after passing through the first eccentric lens 105. Thus, the parabolic adjustable reflector 106 is used to incident on the sample material 107 at different incident angles, so that the incident angle of the sample material 107 is near the Brewster angle θ of the sample material 107. 1′, 2′, and 3′ are beams emitted from the sample material 107.

[0028] Specifically, for the same beam of light, the control module 104 sets the same offset amount and opposite offset angle for the first eccentric lens 105 and the second eccentric lens 109, so that the direction in which the same beam of light first enters the adjusting mirror 106 is opposite to the direction in which it last exits the adjusting mirror 106.

[0029] Specifically, the light beam undergoes three reflections when it passes through the adjustment mirror 106. The first reflection occurs on a parabolic surface on one side of the adjustment mirror 106, the second reflection occurs on the sample material 107 exposed under the hole at the bottom of the adjustment mirror 106, and the third reflection occurs on a parabolic surface on the other side of the adjustment mirror 106.

[0030] Specifically, the control module 104 can be the same control module 104 to control the first eccentric lens 105 and the second eccentric lens 109, or it can be two control modules 104 to control the first eccentric lens 105 and the second eccentric lens 109 respectively. The specific configuration can be determined based on the space requirements and cost considerations of the device.

[0031] This invention, by setting a parabolic adjustable reflector 106, allows the light beam to be incident on the sample material 107 from different angles. This allows the incident angle of the light beam on the sample material 107 to approach the Brewster angle θ of the sample material 107 under the adjustment of the first eccentric lens 105. Since the reflectivity of the light incident near the Brewster angle θ changes significantly, highly sensitive measurement and identification of the sample material 107 can be achieved, resulting in more accurate sample parameters.

[0032] In one embodiment, the light source 101 can be a broadband light source 101 such as a halogen lamp or a xenon lamp, or a monochromatic light source 101 such as a laser.

[0033] In one embodiment, when the light beam enters the aperture of the adjusting mirror 106 at a preset angle after the first reflection, the Brewster angle of the sample material 107 is α, and the range of the preset angle is α ± 3°.

[0034] The present invention obtains an ellipsometer with higher measurement sensitivity by setting the incident angle range of the light beam incident on the adjusting reflector 106.

[0035] In one embodiment, light beams incident on the aperture of the adjusting mirror 106 at different preset angles are all incident on the adjusting mirror 106 in mutually parallel directions.

[0036] In one embodiment, the first reflector 103 and / or the second reflector 110 are motor-controlled angle-adjustable reflectors or MEMS reflector structures.

[0037] Specifically, the deflection angles of the first reflector 103 and the second reflector 110 are adjusted to make the first reflector 103 and the second reflector 110 symmetrical about the axis of symmetry of the adjusting reflector 106.

[0038] This invention increases the amount of adjustable parameters for the incident angle of the beam onto the sample material 107 by setting the deflection angle of the reflector to be adjustable, thereby further improving the sensitivity and adjustability of the ellipsometer.

[0039] In one embodiment, the photodetector 112 is a spectrometer.

[0040] In one embodiment, such as Figures 2-3 As shown, a compensator 113 is provided between the polarizer 102 and the first reflector 103; and / or a compensator 113 is provided between the analyzer 111 and the second reflector 110.

[0041] By setting up a compensator 113, the present invention can automatically compensate for the beam phase deflection caused by the sample material 107, thereby obtaining the beam phase offset caused by the sample material 107. The parameters of the sample material 107 can be directly calculated based on the compensation amount, without needing to obtain the polarization angle of the polarizer 102 or the analyzer 111, thus simplifying the calculation. Example 2:

[0042] This invention provides a measurement method for an ellipsometric measuring device, wherein the measurement method uses any one of the ellipsometric measuring devices described in Embodiment 1, and the measurement method includes: Step 1: Light source 101 emits a beam of light; Step 2: The polarizer 102 is located between the light source 101 and the first reflector 103, so that the light beam generated by the light source 101 becomes polarized light with a preset polarization state; the first reflector 103 reflects the light beam, so that the light beam enters the first eccentric lens 105; the control module 104 controls the position offset and offset direction of the first eccentric lens 105, so that the light beam passes through the first eccentric lens 105 and enters the adjusting reflector 106, and after the first reflection, enters the hole of the adjusting reflector 106 at a preset angle; Step 3: After the light beam is incident on the surface of the sample material 107 exposed by the hole, it is reflected a second time onto the adjusting mirror 106. After the light beam is reflected a third time from the adjusting mirror 106, it is incident on the second eccentric lens 109. The position of the third reflection of the light beam on the adjusting mirror 106 is symmetrical to the position of the first reflection along the axis of symmetry of the adjusting mirror 106. Step 4: The control module 104 controls the position offset and offset direction of the second eccentric lens 109, so that the light beam passes through the second eccentric lens 109 and enters the second reflector 110, and is reflected to the photodetector 112; before the light beam enters the photodetector 112, the analyzer 111 is located between the second reflector 110 and the photodetector 112, restricting only polarized light with a preset polarization state from passing through the light beam emitted from the second reflector 110; Step 5: The photodetector 112 is used to analyze the properties of the incident light beam to obtain the parameters of the sample material 107.

[0043] The measurement method of the elliptic polarization measuring device of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the above order does not strictly represent the measurement method order of the elliptic polarization measuring device protected by the present invention, and those skilled in the art can make changes according to the actual preparation steps.

[0044] First, in step 1, the light source 101 emits a beam of light.

[0045] Then, in step 2, the polarizer 102 is located between the light source 101 and the first reflector 103, so that the light beam generated by the light source 101 becomes polarized light with a preset polarization state; the first reflector 103 reflects the light beam, so that the light beam enters the first eccentric lens 105; the control module 104 controls the position offset and offset direction of the first eccentric lens 105, so that the light beam passes through the first eccentric lens 105 and enters the adjusting reflector 106, and after the first reflection, enters the hole of the adjusting reflector 106 at a preset angle.

[0046] Next, in step 3, the light beam is incident on the surface of the sample material 107 exposed by the hole and then reflected a second time onto the adjusting mirror 106. The light beam is reflected a third time from the adjusting mirror 106 and then incident on the second eccentric lens 109. The position of the third reflection of the light beam on the adjusting mirror 106 is symmetrical to the position of the first reflection along the axis of symmetry of the adjusting mirror 106.

[0047] Then, in step 4, the control module 104 controls the position offset and offset direction of the second eccentric lens 109, so that the light beam passes through the second eccentric lens 109 and enters the second reflector 110, and is reflected to the photodetector 112. Before the light beam enters the photodetector 112, the analyzer 111 is located between the second reflector 110 and the photodetector 112, restricting only polarized light with a preset polarization state from passing through the light beam emitted from the second reflector 110.

[0048] Specifically, the control module 104 controls the first eccentric lens 105 and the second eccentric lens 109 as an operation that needs to be performed after changing different sample materials 107. However, when the same sample material 107 is used repeatedly and the light source 101 is incident from the same position, it is not necessary to repeatedly adjust the eccentric lens, but it can be adjusted each time to ensure the accuracy of the incident angle.

[0049] In one embodiment, either the polarizer 102 or the analyzer 111 can be set to achieve the function of obtaining polarized light, while setting both the polarizer 102 and the analyzer 111 can make the polarization angle of the obtained polarized light more accurate.

[0050] Finally, in step 5, the photodetector 112 is used to analyze the properties of the incident light beam to obtain the parameters of the sample material 107.

[0051] In one embodiment, the photodetector 112 processes the received beam energy and the beam energy emitted by the light source 101 to obtain the angle of the polarizer 102 and / or the angle of the analyzer 111, thereby obtaining the ellipsoid parameters, and correspondingly obtaining the optical constants and film thickness of the sample material 107.

[0052] Specifically, the process of calculating the elliptic deviation parameters is as follows: Jones vector of the beam emitted from light source 101 E for: (1) The beam emitted from polarizer 102 is linearly polarized light, and its matrix is ​​as follows: P The rotation matrix is R p (2) (3) Jones matrix of sample material 107 S for: (4) The analyzer 111 has a matrix A and a rotation matrix R. A (5) (6) The signal received by the detector is E D : (7) Energy I detected by the detector D for: (8) in For E D The Hermitian conjugate matrix.

[0053] Substituting equations (1)-(7) into equation (8) and rearranging, we get: (9) Where α and β are Fourier coefficients:

[0054]

[0055] When the angle P of polarizer 102 and the angle A of analyzer 111 are known, the ellipticity parameters Ψ and Δ can be obtained, thereby obtaining the optical constants and film thickness of the sample material 107 under test.

[0056] Specifically, if only the angle P of the polarizer 102 or the angle A of the analyzer 111 is known, the parameters of the sample material 107 can be obtained directly without calculating the ellipticity parameters.

[0057] In one embodiment, before the light beam is incident from the polarizer 102 onto the first reflector 103, a compensator 113 is disposed between the polarizer 102 and the first reflector 103 to compensate for the phase delay caused by the sample material 107; and / or before the light beam is incident from the second reflector 110 onto the analyzer 111, a compensator 113 is disposed between the analyzer 111 and the second reflector 110 to compensate for the phase delay caused by the sample material 107; the photodetector 112 calculates the optical constants and film thickness of the sample material 107 by processing the received light beam energy and the phase delay compensated by the compensator 113.

[0058] Specifically, when the compensator 113 is set, the angle of the polarizer 102 or the analyzer 111 is not required. The parameters of the sample material can be calculated by simply using the angle of the compensator 113 in conjunction with the beam energy obtained by the photodetector 112.

[0059] In one embodiment, when the light beam enters the aperture of the adjusting mirror 106 at a preset angle after the first reflection, the Brewster angle of the sample material 107 is α, and the range of the preset angle is α ± 3°.

[0060] In summary, the elliptic polarization measurement device and method of the present invention can utilize a parabolic surface as a reflective mirror of the sample, allowing the beam to be incident on the sample surface from different positions at different incident angles, thus enabling flexible measurement of different materials. Furthermore, the automatic offset control of the eccentric lens enables simple and precise adjustment of the incident angle. Additionally, the automatic phase deflection compensation of the beam using a compensator simplifies the calculation process of elliptic polarization parameters.

[0061] Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0062] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An elliptic polarization measuring device, characterized in that, The device includes: a light source, a first reflector, a control module, a first eccentric lens, an adjustable reflector, a second eccentric lens, a second reflector, and a photodetector; The adjustable reflector is a parabolic reflector that is symmetrical from left to right. A hole is provided at the bottom of the adjustable reflector. The hole is located on the axis of symmetry of the adjustable reflector, and the sample material is exposed below the hole. The light beam emitted by the light source is reflected by the first reflector and then enters the first eccentric lens. The control module controls the position offset and offset direction of the first eccentric lens, so that the light beam passes through the first eccentric lens and enters the adjusting reflector. After a first reflection, it enters the aperture of the adjusting reflector at a preset angle. After the light beam enters the surface of the sample material exposed by the aperture, it is reflected a second time onto the adjusting reflector. After a third reflection from the adjusting reflector, the light beam enters the second eccentric lens. The position of the third reflection on the adjusting reflector is symmetrical to the position of the first reflection along the axis of symmetry of the adjusting reflector. Light beams entering the aperture of the adjusting reflector at different preset angles all enter the adjusting reflector in mutually parallel directions. The control module controls the position offset and offset direction of the second eccentric lens, so that the light beam passes through the second eccentric lens and enters the second reflector, and is reflected to the photodetector. The photodetector is used to analyze the properties of the incident light beam to obtain the parameters of the sample material. A polarizer is disposed between the light source and the first reflector, the polarizer being used to make the light beam generated by the light source polarized light with a preset polarization state; and / or an analyzer is disposed between the second reflector and the photodetector, the analyzer being used to restrict only the polarized light with a preset polarization state from passing through the light beam emitted from the second reflector; The first and second reflectors are motor-controlled, angle-adjustable reflectors or MEMS reflector structures.

2. The elliptic polarization measuring device according to claim 1, characterized in that, When the light beam is reflected for the first time and enters the aperture of the adjusting mirror at a preset angle, the Brewster angle of the sample material is α, and the range of the preset angle is α ± 3°.

3. The elliptic polarization measuring device according to claim 1, characterized in that, The photodetector is a spectrometer.

4. The elliptic polarization measuring device according to claim 1, characterized in that, A compensator is provided between the polarizer and the first reflector; and / or a compensator is provided between the analyzer and the second reflector.

5. A measurement method for an ellipsometric measuring device, characterized in that, The measurement method is performed using the ellipsometric measuring device according to any one of claims 1-4, and the measurement method includes: The light source emits a beam of light; The first reflector reflects the light beam, causing the light beam to enter the first eccentric lens. The control module controls the position offset and offset direction of the first eccentric lens, so that the light beam passes through the first eccentric lens and enters the adjustment reflector, and after the first reflection, enters the hole of the adjustment reflector at a preset angle. After the light beam is incident on the surface of the sample material exposed by the hole, it is reflected a second time onto the adjusting mirror. After being reflected a third time from the adjusting mirror, the light beam is incident on the second eccentric lens. The position of the third reflection of the light beam on the adjusting mirror is symmetrical to the position of the first reflection along the axis of symmetry of the adjusting mirror. The control module controls the position offset and offset direction of the second eccentric lens, so that the light beam passes through the second eccentric lens, enters the second reflecting mirror, and is reflected to the photodetector. The photodetector is used to analyze the properties of the incident light beam in order to obtain the parameters of the sample material; Before the light beam enters the first reflector, a polarizer is located between the light source and the first reflector, so that the light beam generated by the light source becomes polarized light with a preset polarization state; and / or before the light beam enters the photodetector, an analyzer is located between the second reflector and the photodetector, restricting only polarized light with a preset polarization state from passing through the light beam emitted from the second reflector.

6. The measurement method of the elliptic polarization measuring device according to claim 5, characterized in that, The photodetector processes the received beam energy and the beam energy emitted by the light source to obtain the angle of the polarizer and / or the angle of the analyzer, thereby obtaining the ellipsometric parameters, and correspondingly obtaining the optical constants and film thickness of the sample material.

7. The measurement method of the elliptic polarization measuring device according to claim 5, characterized in that, The light beam is incident from the polarizer to the first reflector, and a compensator is disposed between the polarizer and the first reflector to compensate for the phase delay caused by the sample material; and / or the light beam is incident from the second reflector to the analyzer, and a compensator is disposed between the analyzer and the second reflector to compensate for the phase delay caused by the sample material. The photodetector processes the received beam energy and the phase delay compensated by the compensator to calculate the optical constants and film thickness of the sample material.

8. The measurement method of the elliptic polarization measuring device according to claim 5, characterized in that, When the light beam is reflected for the first time and enters the aperture of the adjusting mirror at a preset angle, the Brewster angle of the sample material is α, and the range of the preset angle is α ± 3°.

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