Dual-mode ellipsometry device and method based on wafer inclined placement

Abstract

The invention discloses a dual-mode ellipsometry device and method based on wafer oblique placement, and the device comprises a base, and a reflection ellipsometry module, a transmission ellipsometry module and a vertical self-positioning sample stage which are arranged above the base, and a wafer sample is vertically placed on the vertical self-positioning sample stage. The reflection ellipsometry measurement module comprises a reflection polarization arm and a reflection polarization detection arm, the reflection polarization arm and the reflection polarization detection arm are used for conducting reflection ellipsometry detection on a wafer sample to obtain a first ellipsometry parameter, and the reflection polarization arm and the reflection polarization detection arm are symmetrically arranged in the normal direction of the surface of the wafer sample during detection; the transmission ellipsometry measurement module comprises a transmission polarization arm and a transmission polarization detection arm, the transmission polarization arm and the transmission polarization detection arm are used for carrying out transmission ellipsometry detection on the wafer sample to obtain a second ellipsometry parameter, and the transmission polarization arm and the transmission polarization detection arm are located on the same straight line and are both perpendicular to the surface of the wafer sample during detection. According to the invention, the problem of low precision and efficiency caused by poor measurement flexibility is solved.

Description

Technical Field

[0001] This invention relates to the field of ellipticity measurement technology, specifically to a dual-mode ellipticity measurement device and method based on a wafer placed at an angle. Background Technology

[0002] Ellipsometry is a non-contact optical measurement technique widely used in semiconductors, materials science, and other fields to measure parameters such as thin film thickness and optical constants. Ellipsometry systems typically employ either reflection or transmission measurement modes. The accuracy of ellipsometry depends on the precision of the measurement coordinate system, requiring instrument calibration before measurement. Switching between modes often necessitates system recalibration, making it difficult to meet the measurement needs of complex samples. Furthermore, with the continuous increase in wafer size, the additional warping caused by gravity and the deviation of the sample surface normal from the measurement coordinate system when the sample is placed horizontally significantly impacts detection accuracy. Therefore, the sample placement method and the flexibility of the measurement system also limit the accuracy and efficiency of the measurement.

[0003] The patent with publication number CN103134592B discloses a transmission-type full Mueller matrix spectroscopic ellipsometer and its measurement method. For various samples, this ellipsometer can achieve rapid and accurate measurements across the entire spectral range. It can obtain the normalized 4×4 order Mueller matrix of the measured sample in a single measurement without changing the system configuration. The instrument's design considers both ellipsometer reflectance and transmission measurement modes, but it does not explicitly explain how the two measurement modes are switched.

[0004] Therefore, there is an urgent need in the field for a device and method that offers flexible mode switching, fast measurement speed, applicability to large-size wafers, effectively reduces additional warping caused by gravity during sample placement, and achieves efficient dual-mode ellipsometric measurement. Summary of the Invention

[0005] The purpose of this application is to provide a dual-mode ellipsometry measurement device and method based on the oblique placement of a wafer to address the aforementioned technical problems.

[0006] In a first aspect, the present invention provides a dual-mode ellipticity measurement device based on a wafer placed at an angle, comprising a base and a reflection ellipticity measurement module, a transmission ellipticity measurement module, and a vertical self-positioning sample stage disposed above the base. The wafer sample is placed vertically on the vertical self-positioning sample stage. The reflection ellipticity measurement module includes a reflection polarization arm and a reflection polarization detector arm. The reflection polarization arm and the reflection polarization detector arm are used to perform reflection ellipticity detection on the wafer sample to obtain a first ellipticity parameter. During detection, the reflection polarization arm and the reflection polarization detector arm are symmetrically arranged along the normal direction of the wafer sample surface. The transmission ellipticity measurement module includes a transmission polarization arm and a transmission polarization detector arm. The transmission polarization arm and the transmission polarization detector arm are used to perform transmission ellipticity detection on the wafer sample to obtain a second ellipticity parameter. During detection, the transmission polarization arm and the transmission polarization detector arm are located on the same straight line and are both perpendicular to the surface of the wafer sample. The reflection ellipticity measurement module and the transmission ellipticity measurement module can be used to perform reflection ellipticity detection and transmission ellipticity detection at the same measurement point on the surface of the wafer sample.

[0007] Preferably, the reflective polarizer arm includes a first light source, a first lens group, a reflective polarizer arm polarizer, and a reflective polarizer arm compensator, all located sequentially on the same optical path; the reflective analyzer arm includes a reflective analyzer arm polarizer, a reflective analyzer arm compensator, a second lens group, and a first spectrometer, all located sequentially on the same optical path; the first light source is located at the corner of the first lens group, and the first spectrometer is located at the focal point of the second lens group; the reflective polarizer arm is used to incident a light beam at a preset angle onto the surface of the wafer sample to be tested, and the reflective analyzer arm is used to detect the change in polarization state of the reflected light beam after reflection from the surface of the wafer sample to be tested, thereby obtaining the first ellipsometric parameter.

[0008] Preferably, the transmission polarizer arm includes a second light source, a third lens group, a transmission polarizer arm polarizer, and a transmission polarizer arm compensator, all located sequentially on the same optical path; the transmission analyzer arm includes a transmission analyzer arm polarizer, a transmission analyzer arm compensator, a fourth lens group, and a second spectrometer, all located sequentially on the same optical path; the second light source is located at the corner of the third lens group, and the second spectrometer is located at the focal point of the fourth lens group; the transmission polarizer arm is used to perpendicularly incident a light beam onto the surface to be tested of the wafer sample, and the transmission analyzer arm is used to detect the change in polarization state of the transmitted light beam after transmission through the surface to be tested of the wafer sample, thereby obtaining the second ellipsoidal parameter.

[0009] Preferably, the system also includes an analysis module, which is used to fit the received first ellipticity parameter and / or second ellipticity parameter with the optical model of the known material to obtain the performance parameters of the wafer sample.

[0010] Preferably, performance parameters include thickness, refractive index, and / or extinction coefficient.

[0011] Preferably, the vertical self-positioning sample stage includes a support frame, a positioning device, and a three-axis displacement stage. The support frame is provided with a support member, and the area opposite to the wafer sample, excluding the support member, is hollowed out. The positioning device is installed on the support member, and the support frame is installed on the three-axis displacement stage. The wafer sample is placed vertically on the positioning device, and the surface on the other side of the wafer sample opposite to the surface to be measured is in contact with the support member. The three-axis displacement stage is used to adjust the measurement point on the surface to be measured on the wafer sample.

[0012] Preferably, the positioning device is a V-shaped component, which includes a wedge surface with a V-shaped opening. When the wafer sample is placed vertically on the wedge surface, the central axis of the V-shaped opening coincides with the diameter direction of the surface of the wafer sample.

[0013] Preferably, the diameter of the wafer sample is in the range of 2 to 12 inches, and the support is provided with several mounting holes, so that the mounting position of the positioning device on the support can be adjusted according to the diameter of the wafer sample.

[0014] Preferably, the base can adjust the tilt angle of the reflection ellipsometer module, the transmission ellipsometer module and the vertical self-positioning sample stage located above it. The base includes an upper frame, a lower frame and a tilt adjustment device. The reflection ellipsometer module, the transmission ellipsometer module and the vertical self-positioning sample stage are set on the upper frame. A tilt adjustment device is provided between the upper frame and the lower frame. The tilt angle of the upper frame relative to the lower frame is adjusted by the tilt adjustment device. The tilt angle is 0~3°.

[0015] Secondly, the present invention provides a dual-mode ellipsometry measurement method based on wafer tilting, employing the dual-mode ellipsometry measurement device based on wafer tilting as mentioned in the first aspect, comprising the following steps: The reflection ellipsometer module and / or the transmission ellipsometer module are calibrated separately. Adjust the tilt angle of the upper surface of the base, place the wafer sample on the vertical self-positioning sample stage, and determine the measurement point of the surface of the wafer sample to be tested. The ellipticity parameters of the measurement points on the surface to be tested of the wafer sample are measured using ellipticity measurement methods in reflection mode and / or transmission mode. The ellipsometric measurement method in reflection mode includes the following steps: Turn on the first light source in the reflection ellipsometric measurement module, adjust the light source power, and turn on the first spectrometer in the reflection ellipsometric measurement module. Adjust the reflection polarization arm in the reflection ellipsometric measurement module so that the beam emitted by the first light source is incident on the measurement point of the wafer sample at a preset angle. Use the reflection analyzer in the reflection ellipsometric measurement module to detect the change in polarization state of the reflected beam after reflection from the wafer sample to obtain the first ellipsometric parameter. The ellipsometric measurement method in transmission mode includes the following steps: Turn on the second light source in the transmission ellipsometric measurement module, adjust the light source power, and turn on the second spectrometer in the transmission ellipsometric measurement module. Adjust the transmission polarization arm in the transmission ellipsometric measurement module so that the beam emitted by the second light source is perpendicularly incident on the measurement point of the wafer sample's surface to be measured. Use the transmission polarization analyzer in the transmission ellipsometric measurement module to detect the change in polarization state of the transmitted beam obtained after passing through the surface to be measured of the wafer sample, and obtain the second ellipsometric parameters. The performance parameters of the wafer sample are obtained by fitting the optical model of the known material based on the first or second elliptic parameter.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The dual-mode ellipsometric measurement device based on oblique placement of wafer mentioned in this invention integrates a reflection ellipsometric measurement module and a transmission ellipsometric measurement module, and proposes a dual-mode measurement method that can be flexibly switched according to actual measurement needs and sample characteristics. There is no need to repeat instrument calibration during the switching process between the two measurement modes. At the same time, the wafer sample does not need to be placed repeatedly, reducing the measurement error caused by different measurement points, reducing the time spent due to changes in measurement methods, and improving measurement efficiency.

[0017] (2) The dual-mode ellipticity measurement device based on obliquely placed wafers mentioned in this invention designs a vertical self-positioning sample stage. The wafer sample is placed vertically on the vertical self-positioning sample stage, and a wafer positioning device is set on the support frame to complete the positioning using the wafer's own gravity. The tilt angle of the device above is adjusted by the tilt adjustment device on the base to reduce the measurement error caused by the additional warping of large-size wafer samples due to gravity.

[0018] (3) The dual-mode elliptic measurement device based on the oblique placement of the wafer mentioned in this invention has both reflection elliptic measurement and transmission elliptic measurement functions, which reduces the number of instruments used in the wafer measurement process, reduces equipment procurement and maintenance costs, and reduces the skill requirements for operators. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a top view schematic diagram of the optical path structure of a dual-mode ellipsometry measurement device based on a wafer tilted at an angle, according to an embodiment of this application. Figure 2This is a side view schematic diagram of a dual-mode ellipsometry measurement device based on a wafer tilted at an angle, according to an embodiment of this application. Figure 3 This is a schematic diagram of the support frame and positioning device of the dual-mode ellipsometry measurement device based on the oblique placement of a wafer, according to an embodiment of this application. Figure 4 This is a schematic diagram of the base of a dual-mode ellipsometry measurement device based on a wafer tilted at an angle, as an embodiment of this application. Figure Descriptions: 100, Reflection polarizer arm; 101, First light source; 102, First lens group; 103, Reflection polarizer arm polarizer; 104, Reflection polarizer arm compensator; 200, Transmission polarizer arm; 201, Second light source; 202, Third lens group; 203, Transmission polarizer arm polarizer; 204, Transmission polarizer arm compensator; 300, Reflection analyzer arm; 301, First spectrometer; 302, Second lens group; 303, Reflection... 304. Reflection polarizer; 400. Transmission polarizer; 401. Second spectrometer; 402. Fourth lens group; 403. Transmission polarizer compensator; 404. Transmission polarizer; 500. Vertical self-positioning sample stage; 501. Support frame; 502. Positioning device; 503. Triaxial displacement stage; 600. Base; 601. Upper frame; 602. Tilt adjustment device; 603. Lower frame. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] Figure 1 and Figure 2This application illustrates an embodiment of a dual-mode ellipticity measurement device based on a wafer placed at an angle. The device includes an analysis module, a base 600, and a reflection ellipticity measurement module, a transmission ellipticity measurement module, and a vertical self-positioning sample stage 500 disposed above the base 600. The wafer sample is placed vertically on the vertical self-positioning sample stage 500. Here, "vertical placement" means that the normal direction of the flat surface of the circular wafer sample is parallel to the upper surface of the base 600. The reflection ellipticity measurement module includes a reflection polarizer arm 100 and a reflection analyzer arm 300. The reflection polarizer arm 100 and the reflection analyzer arm 300 are used to detect the reflection ellipticity of the wafer sample to obtain a first ellipticity parameter, thus achieving ellipticity measurement in reflection mode. During testing, the reflective polarization arm 100 and the reflective polarization analyzer arm 300 are symmetrically arranged along the normal direction of the wafer sample surface. The reflective polarization arm 100 and the reflective polarization analyzer arm 300 are symmetrically set on the left and right sides of the normal direction of the measurement point on the surface to be tested of the wafer sample. The transmission ellipticity measurement module includes a transmission polarization arm 200 and a transmission polarization analyzer arm 400. The transmission polarization arm 200 and the transmission polarization analyzer arm 400 are used to perform transmission ellipticity detection on the wafer sample to obtain the second ellipticity parameter, thus realizing ellipticity measurement in transmission mode. During testing, the transmission polarizer arm 200 and the transmission analyzer arm 400 are located on the same straight line and are both perpendicular to the surface of the wafer sample. The transmission polarizer arm 200 and the transmission analyzer arm 400 are respectively positioned on both sides of the plane containing the flat surface of the wafer sample. The reflection ellipsometric measurement module and the transmission ellipsometric measurement module can be used to perform reflection ellipsometric detection and transmission ellipsometric detection on the same measurement point on the surface of the wafer sample. This enables ellipsometric measurement of the same measurement point on the surface of the wafer sample in dual modes. Alternatively, only one of the reflection ellipsometric measurement module and the transmission ellipsometric measurement module can be used to perform ellipsometric measurement of the measurement point on the surface of the wafer sample in one mode. Further, the analysis module can be used to fit the received first ellipsometric parameters and / or second ellipsometric parameters with the optical model of the known material to obtain the performance parameters of the wafer sample. The performance parameters include thickness, refractive index, and / or extinction coefficient. The specific fitting process is a conventional method in material analysis and will not be elaborated here. The analysis module is connected to the first spectrometer 301 and the second spectrometer 401 respectively to receive the measured first ellipticity parameter and / or second ellipticity parameter.

[0023] In a specific embodiment, refer to Figure 1The reflective polarizer 100 includes a first light source 101, a first lens group 102, a reflective polarizer 103, and a reflective polarizer compensator 104, all located sequentially on the same optical path. The reflective analyzer 300 includes a reflective analyzer 304, a reflective analyzer compensator 303, a second lens group 302, and a first spectrometer 301, all located sequentially on the same optical path. The first light source 101 is located at a corner of the first lens group 102, and the first spectrometer 301 is located at the focal point of the second lens group 302. The reflective polarizer 100 is used to incident a light beam onto the surface of the wafer sample at a preset angle. The reflective analyzer 300 is used to detect the change in polarization state of the reflected light beam after reflection from the surface of the wafer sample, thereby obtaining the first ellipsometric parameter. The light emitted from the first light source 101 is first converted into a beam by the first lens group 102. This beam then passes through the reflective polarizer 103 and the reflective polarizer compensator 104, and is converted into polarized light. It is then incident at a specific angle onto the measurement point on the surface of the wafer sample. The polarized light reflected from the measurement point on the surface of the wafer sample is incident on the reflective analyzer 304 and the reflective analyzer compensator 303, and then, after passing through the second lens group 302, is transmitted to the first spectrometer 301. The first spectrometer 301 acquires the ellipsometric spectral data and converts it into the first ellipsometric parameter. Delta and Psi Therefore, the reflection ellipsometric measurement module can be used to detect the reflection ellipsometrics of wafer samples.

[0024] In a specific embodiment, the transmission polarizer 200 includes a second light source 201, a third lens group 202, a transmission polarizer 203, and a transmission polarizer compensator 204, all located sequentially on the same optical path; the transmission analyzer 400 includes a transmission analyzer 404, a transmission analyzer compensator 403, a fourth lens group 402, and a second spectrometer 401, all located sequentially on the same optical path; the second light source 201 is located at the corner of the third lens group 202, and the second spectrometer 401 is located at the focal point of the fourth lens group 402; the transmission polarizer 200 is used to perpendicularly incident a light beam onto the surface to be tested of the wafer sample, and the transmission analyzer 400 is used to detect the change in polarization state of the transmitted light beam obtained after transmission through the surface to be tested of the wafer sample, thereby obtaining the second ellipsoidal parameter. The light emitted by the second light source 201 is first converted into a beam by the third lens group 202. This beam is then converted into polarized light after passing through the transmission polarizer 203 and the transmission polarizer compensator 204, and is incident perpendicularly on the measurement point on the surface of the wafer sample to be tested. The polarized light transmitted through the measurement point on the surface of the wafer sample to be tested is incident on the transmission analyzer 404 and the transmission analyzer compensator 403, and then transmitted to the second spectrometer 401 after passing through the fourth lens group 402. The second spectrometer 401 obtains the elliptic spectrum data and converts it into the second ellipticity parameters Δ and Ψ. Therefore, the transmission ellipticity measurement module can be used to detect the transmission ellipticity of the wafer sample.

[0025] In one example, the first light source 101 and the second light source 201 can be selected as SLS201L( / M) halogen tungsten light sources with a wavelength range of 360~2600nm and a peak wavelength of 1000nm; the first spectrometer 301 and the second spectrometer 401 can be selected as Solvay CCS / M spectrometers with a wavelength range of 200~1000nm and an accuracy of <2.0nm.

[0026] In a specific embodiment, refer to Figure 3 The vertical self-positioning sample stage 500 includes a support frame 501, a positioning device 502, and a three-axis displacement stage 503. The support frame 501 is provided with a support member, and the area opposite to the wafer sample, except for the support member, is hollowed out. Therefore, the transmission ellipsometric measurement of the wafer sample can be realized. In the transmission ellipsometric measurement mode, the light beam emitted by the transmission polarization arm 200 can be transmitted on the wafer sample, and the transmitted light is not blocked by the support frame 501. The positioning device 502 is mounted on the support, and the support frame 501 is mounted on the three-axis displacement stage 503. The wafer sample is placed vertically on the positioning device 502, with the surface opposite the test surface of the wafer sample in contact with the support. The diameter of the wafer sample ranges from 2 to 12 inches. The support has several mounting holes, allowing the mounting position of the positioning device 502 on the support to be adjusted according to the diameter of the wafer sample. If the diameter of the wafer sample is 12 inches, the positioning device 502 can be installed using the lowest mounting hole, thus meeting the measurement requirements of wafers of different sizes. The three-axis displacement stage 503 can adjust the movement of the support frame 501 in the x, y, and z directions to adjust the measurement point on the test surface of the wafer sample. To meet the measurement requirements of a 12-inch wafer, the sample stage length (A) × width (B) × height (C) is approximately 500 mm × 100 mm × 700 mm. In one example, the support frame 501 has two support members, a first support member and a second support member, which are perpendicular to each other. The first support member is perpendicular to the upper surface of the base 600, and the second support member is parallel to the upper surface of the base 600. The positioning device 502 is mounted on the first support member and located below the point where the first and second support members intersect. In other examples, support members of other shapes or mounting positions can also be designed. The wafer sample can be placed vertically using the support members.

[0027] In a specific embodiment, the positioning device 502 is a V-shaped component, which includes a wedge surface with a V-shaped opening. When the wafer sample is placed vertically on the wedge surface, the central axis of the V-shaped opening coincides with the diameter direction of the wafer sample's surface. According to the wafer size design, the wafer sample slides down to contact the V-shaped component under its own gravity. When the outer cylindrical surface of the wafer is placed on the V-shaped component, the wafer sample's radial axis will automatically align with the symmetrical center plane of the V-shaped component. This method is simple to operate, has high positioning efficiency, and good alignment.

[0028] In a specific embodiment, the base 600 can adjust the tilt angle of the reflection ellipsometer module, the transmission ellipsometer module, and the vertical self-positioning sample stage 500 located above it. The base 600 includes an upper frame 601, a lower frame 603, and a tilt adjustment device 602. The reflection ellipsometer module, the transmission ellipsometer module, and the vertical self-positioning sample stage 500 are mounted on the upper frame 601. The tilt adjustment device 602 is provided between the upper frame 601 and the lower frame 603. The tilt angle of the upper frame 601 relative to the lower frame 603 is adjusted by the tilt adjustment device 602, and the tilt angle is 0~3°. That is, the base 600 can adjust the angle between the planes where the upper frame 601 and the lower frame 603 are located within the range of 0~3°. When the upper frame 601 and the lower frame 603 are parallel, the dimensions satisfy length (D) × width (E) × height (F) ≈ 900mm × 700mm × 100mm. By adjusting the angle between the upper frame 601 and the lower frame 603, the wafer sample is made to form a small angle with the vertical plane, which helps to reduce the measurement error caused by additional warping during the measurement of large-size wafer samples. In one example, the tilt adjustment device 602 can be a wedge block. By adjusting the position of the wedge block on the lower frame 603, the angle between the planes containing the upper frame 601 and the lower frame 603 can be adjusted.

[0029] Correspondingly, this application provides a dual-mode ellipticity measurement method based on wafer tilting, employing the dual-mode ellipticity measurement device based on wafer tilting as described above, including the following steps: The reflection ellipsometer module and / or the transmission ellipsometer module are calibrated separately. Adjust the tilt angle of the upper surface of the base 600, place the wafer sample on the vertical self-positioning sample stage 500, and determine the measurement point of the surface to be measured on the wafer sample. The ellipticity parameters of the measurement points on the surface to be tested of the wafer sample are measured using ellipticity measurement methods in reflection mode and / or transmission mode. The ellipsometric measurement method in reflection mode includes the following steps: Turn on the first light source 101 in the reflection ellipsometric measurement module, adjust the light source power, and turn on the first spectrometer 301 in the reflection ellipsometric measurement module. Adjust the reflection polarization arm 100 in the reflection ellipsometric measurement module so that the light beam emitted by the first light source 101 is incident on the measurement point of the wafer sample at a preset angle. Use the reflection analyzer arm 300 in the reflection ellipsometric measurement module to detect the change in polarization state of the reflected light beam after reflection from the wafer sample to obtain the first ellipsometric parameters. The ellipsometric measurement method in transmission mode includes the following steps: Turn on the second light source 201 in the transmission ellipsometric measurement module, adjust the light source power, and turn on the second spectrometer 401 in the transmission ellipsometric measurement module. Adjust the transmission polarization arm 200 in the transmission ellipsometric measurement module so that the light beam emitted by the second light source 201 is perpendicularly incident on the measurement point of the wafer sample's surface to be measured. Use the transmission polarization analyzer arm 400 in the transmission ellipsometric measurement module to detect the change in polarization state of the transmitted light beam obtained after passing through the surface to be measured of the wafer sample, and obtain the second ellipsometric parameters. The performance parameters of the wafer sample are obtained by fitting the optical model of the known material based on the first or second elliptic parameter.

[0030] Specifically, the reflection ellipsometric measurement module and the transmission ellipsometric measurement module proposed in the embodiments of this application correspond to the ellipsometric measurement method in reflection mode and the ellipsometric measurement method in transmission mode, respectively. In one example, taking the ellipsometric measurement method in reflection mode alone as an example, it includes the following steps: S11, turn on the first light source 101, adjust the light source power, turn on the first spectrometer 301, calibrate the reflection ellipsometer measurement module using standard materials to ensure the accuracy of the measurement, and turn off the first light source 101 and the first spectrometer 301; S12, ensure that the surface of the wafer sample to be tested is flat and free of contamination, place it on the vertical self-positioning sample stage 500, and adjust the measurement point position of the surface of the wafer sample to be tested. S13, turn on the first light source 101, adjust the light source power, turn on the first spectrometer 301, adjust the reflector arm 100, so that the light beam is incident on the measurement point of the wafer sample surface to be measured at a specific angle. S14, the change in the polarization state of the reflected beam is detected by the reflection analyzer 300 to obtain the first ellipticity parameter; S15. Based on the measured first ellipticity parameter, the optical model established using known materials is fitted to obtain the material's performance parameters.

[0031] In another example, taking the ellipsometric measurement method in a single transmission mode as an example, it includes the following steps: S21, turn on the second light source 201, adjust the light source power, turn on the second spectrometer 401, calibrate the transmission ellipsometer measurement module using standard materials to ensure the accuracy of the measurement, and turn off the second light source 201 and the second spectrometer 401. S22, ensure that the surface of the wafer sample to be tested is flat and free of contamination, place it on the vertical self-positioning sample stage 500, and adjust the measurement point position of the surface of the wafer sample to be tested. S23, turn on the second light source 201, adjust the light source power, turn on the second spectrometer 401, adjust the transmission polarizer arm 200 and the transmission analyzer arm 400 to be in a straight line, so that the beam is perpendicularly incident on the measurement point of the wafer sample surface to be measured. S24, the change in the polarization state of the reflected beam is detected by the transmission polarizer 400 to obtain the second ellipsoid parameter; S25. Based on the measured second ellipticity parameter, the optical model established using known materials is fitted to obtain the material's performance parameters.

[0032] The ellipsometric measurement methods described above, using both reflection and transmission modes, can be employed to measure the same measurement point on the surface of a wafer sample. The reflection ellipsometric module performs reflection detection on a measurement point on the surface of the wafer sample, while the transmission ellipsometric module performs transmission detection on the same measurement point. After calibration of both modes during the measurement process, the sample does not need to be repositioned or the instrument recalibrated when switching between modes, thus shortening the detection time and avoiding errors caused by coordinate system changes.

[0033] The optical paths of the reflection ellipsometric measurement module and the transmission ellipsometric measurement module mentioned in the embodiments of this application are independent, and they have independent light sources and spectrometers. Therefore, the measurement modes can be switched using software, and synchronous dual-mode measurement at the same measurement site can also be achieved.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-mode ellipsometry measurement device based on a wafer tilted at an angle, characterized in that, The system includes a base and a reflection ellipsometer module, a transmission ellipsometer module, and a vertical self-positioning sample stage mounted on the base. A wafer sample is placed vertically on the vertical self-positioning sample stage. The reflection ellipsometer module includes a reflection polarizer arm and a reflection polarizer arm. The reflection ellipsometer arm and reflection polarizer arm are used to detect the reflection ellipsometer of the wafer sample to obtain a first ellipsometer parameter. During detection, the reflection polarizer arm and reflection polarizer arm are symmetrically arranged along the normal direction of the wafer sample surface. The transmission ellipsometer module includes a transmission polarizer arm and a transmission polarizer arm. The transmission polarizer arm and transmission polarizer arm are used to detect the transmission ellipsometer of the wafer sample to obtain a second ellipsometer parameter. During detection, the transmission polarizer arm and transmission polarizer arm are located on the same straight line and are both perpendicular to the surface of the wafer sample. The reflection ellipsometer module and the transmission ellipsometer module can be used to perform reflection ellipsometer and transmission ellipsometer detection at the same measurement point on the surface of the wafer sample.

2. The dual-mode ellipsometry measurement device based on obliquely placed wafers according to claim 1, characterized in that, The reflective polarizing arm includes a first light source, a first lens group, a reflective polarizing arm polarizer, and a reflective polarizing arm compensator, all located sequentially on the same optical path; the reflective polarizing arm includes a reflective polarizing arm analyzer, a reflective polarizing arm compensator, a second lens group, and a first spectrometer, all located sequentially on the same optical path; the first light source is located at the corner of the first lens group, and the first spectrometer is located at the focal point of the second lens group; The light beam is incident at a preset angle onto the test surface of the wafer sample using the reflective polarizer arm, and the polarization state change of the reflected light beam after reflection from the test surface of the wafer sample is detected using the reflective analyzer arm to obtain the first ellipsometric parameter.

3. The dual-mode ellipsometry measurement device based on obliquely placed wafers according to claim 1, characterized in that, The transmission polarizing arm includes a second light source, a third lens group, a transmission polarizing arm polarizer, and a transmission polarizing arm compensator, all located sequentially on the same optical path; the transmission analyzing arm includes a transmission analyzing arm polarizer, a transmission analyzing arm compensator, a fourth lens group, and a second spectrometer, all located sequentially on the same optical path; the second light source is located at the corner of the third lens group, and the second spectrometer is located at the focal point of the fourth lens group. The transmission polarizer arm is used to perpendicularly incident a light beam onto the surface to be tested of the wafer sample. The transmission analyzer arm is used to detect the change in polarization state of the transmitted light beam after it has passed through the surface to be tested of the wafer sample, and the second ellipsometric parameter is obtained.

4. The dual-mode ellipsometry measurement device based on wafer tilting as described in claim 1, characterized in that, It also includes an analysis module, which is used to fit the received first ellipticity parameter and / or second ellipticity parameter with the optical model of the known material to obtain the performance parameters of the wafer sample.

5. The dual-mode ellipsometry measurement device based on obliquely placed wafers according to claim 4, characterized in that, The performance parameters include thickness, refractive index, and / or extinction coefficient.

6. The dual-mode ellipsometry measurement device based on wafer tilting as described in claim 1, characterized in that, The vertical self-positioning sample stage includes a support frame, a positioning device, and a three-axis displacement stage. The support frame is provided with a support member, and the area opposite to the wafer sample, excluding the support member, is hollowed out. The positioning device is mounted on the support member, and the support frame is mounted on the three-axis displacement stage. The wafer sample is placed vertically on the positioning device, and the surface on the other side of the wafer sample opposite to the surface to be measured is in contact with the support member. The three-axis displacement stage is used to adjust the measurement point on the surface to be measured on the wafer sample.

7. The dual-mode ellipsometry measurement device based on wafer tilting as described in claim 6, characterized in that, The positioning device is a V-shaped component, which includes a wedge surface with a V-shaped opening. When the wafer sample is placed vertically on the wedge surface, the central axis of the V-shaped opening coincides with the diameter direction of the surface of the wafer sample.

8. The dual-mode ellipsometry measurement device based on wafer tilting as described in claim 6, characterized in that, The diameter of the wafer sample ranges from 2 to 12 inches. The support has several mounting holes, and the mounting position of the positioning device on the support can be adjusted according to the diameter of the wafer sample.

9. The dual-mode ellipsometry measurement device based on obliquely placed wafers according to claim 1, characterized in that, The base allows adjustment of the tilt angle of the reflection ellipsometer module, the transmission ellipsometer module, and the vertical self-positioning sample stage located above it. The base includes an upper frame, a lower frame, and a tilt adjustment device. The reflection ellipsometer module, the transmission ellipsometer module, and the vertical self-positioning sample stage are mounted on the upper frame. A tilt adjustment device is provided between the upper frame and the lower frame to adjust the tilt angle of the upper frame relative to the lower frame. The tilt angle is 0~3°.

10. A dual-mode ellipsometry measurement method based on wafer tilting, employing the dual-mode ellipsometry measurement device based on wafer tilting as described in any one of claims 1-9, characterized in that, Includes the following steps: The reflection ellipsometer module and / or the transmission ellipsometer module are calibrated separately. Adjust the tilt angle of the upper surface of the base, place the wafer sample on the vertical self-positioning sample stage, and determine the measurement point of the surface to be tested on the wafer sample. The ellipticity parameters of the measurement points on the surface to be tested of the wafer sample are measured using an ellipticity measurement method in reflection mode and / or an ellipticity measurement method in transmission mode. The ellipsometric measurement method in the reflection mode includes the following steps: Turn on the first light source in the reflection ellipsometric measurement module, adjust the light source power, and turn on the first spectrometer in the reflection ellipsometric measurement module. Adjust the reflection polarization arm in the reflection ellipsometric measurement module so that the light beam emitted by the first light source is incident on the measurement point of the wafer sample at a preset angle. Use the reflection analyzer in the reflection ellipsometric measurement module to detect the change in polarization state of the reflected light beam after reflection from the wafer sample to obtain the first ellipsometric parameter. The ellipsometric measurement method in the transmission mode includes the following steps: Turn on the second light source in the transmission ellipsometric measurement module, adjust the light source power, and turn on the second spectrometer in the transmission ellipsometric measurement module. Adjust the transmission polarization arm in the transmission ellipsometric measurement module so that the light beam emitted by the second light source is perpendicularly incident on the measurement point of the surface to be measured of the wafer sample. Use the transmission polarization analyzer in the transmission ellipsometric measurement module to detect the change in polarization state of the transmitted light beam obtained after passing through the surface to be measured of the wafer sample, and obtain the second ellipsometric parameters. The performance parameters of the wafer sample are obtained by fitting the optical model of the known material based on the first or second elliptic parameter.

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