Method and device for synchronous measurement of film surface and interface profile based on waveband division multispectrum

Abstract

The application belongs to the technical field of precision instruments, and discloses a film surface and interface profile synchronous measurement method and device based on a split-waveband multispectrum, wherein the measurement device comprises a light splitting module, a dichroic mirror, a reference mirror, an imaging lens and a spectrometer; the light splitting module is used for splitting the received light into a first light beam and a second light beam; the first light beam is reflected by the film to be measured in the full waveband; the light in part of the waveband in the second light beam is reflected by the reference mirror and interferes with the light of the corresponding waveband reflected by the film; and the interference light and the remaining light reflected by the film enter the spectrometer. The film sample surface and interface profile can be obtained by processing the spectral image; the filtering function of the dichroic mirror makes it possible to obtain the interference spectrum and the reflection spectrum at the same time, and the measurement of the film sample surface and interface profile under single exposure is realized; and the interference spectrum and the reflection spectrum of the measurement sample can be directly obtained without multiple exposures or reprocessing of the directly obtained light intensity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field related to precision instruments, and more particularly, to a thin film surface and interface profile synchronous measurement method and device based on a sub-band multispectrum. BACKGROUND

[0002] Core elements composed of microstructures of thin films are widely used in modern industry, including integrated circuits, sensors, and LED industries. The thin film surface and interface profile size, i.e., the thickness of the thin film and the size of the interface profile, directly affects the performance of the device. In order to improve the level of intelligent manufacturing technology, not only should the process conditions be optimized, but also the metrology for measuring and checking the thin film should be optimized.

[0003] White light reflectance spectroscopy technology uses white light as a light source, and obtains the thin film interference light intensity of different wavelengths through the principle of thin film interference and the principle of spectral light splitting to solve the measurement of thin film thickness. The white light reflectance spectrometer is a classic measuring instrument of white light reflectance spectroscopy technology, and the specific process is to make the reflected light of the thin film sample incident to the spectrometer, the spectrometer splits the thin film interference light to obtain the light intensity of different wavelengths, i.e., the spectrum signal of the thin film interference light, and the thin film thickness is solved by data processing of the spectrum signal, such as fitting reflectivity and extreme point method. Therefore, the white light reflectance spectrometer can measure the thin film thickness but cannot measure the height information, and thus cannot measure the interface profile of the thin film.

[0004] White light spectral interference technology also uses white light as a light source, and obtains the interference light intensity of different wavelengths through the principle of light interference and spectral light splitting to solve the measurement of sample characteristics. The spectral white light interferometer is a classic measuring instrument of white light spectral interference technology, which can measure the surface and interface profile of the thin film sample. The specific process is that the reference mirror and the reflected light of the measurement sample interfere, the interference light is incident to the spectrometer, the spectrum signal of the reference mirror and the measurement sample is collected, and the thin film thickness in the thin film sample is solved by data processing of the interference light signal, thereby completing the measurement of the surface and interface profile.

[0005] The specific process of signal decomposition involves using digital signal correlation algorithms to demodulate the phase information of the interference terms in the spectral signal of the interferometric light, thereby measuring the thickness and interface profile of the transparent film. However, when the film thickness is reduced below a certain threshold, the difference in phase spectrum information between films of different thicknesses is very small, making it difficult to obtain accurate phase during demodulation and ensuring measurement reliability. To achieve the measurement of thinner film thicknesses on substrates with varying interface profiles, researchers have introduced reflection spectrum technology based on white light spectral interferometry. This is because the difference in reflection spectra between thinner films of different thicknesses is relatively large, and measuring film thickness by fitting the reflection spectrum is more reliable. Methods have emerged that involve adding an optical shutter to a spectral white light interferometer to obtain the reflection spectrum and then fitting the reflectivity to measure the film thickness, as well as adding polarization elements and a polarization camera to a spectral white light interferometer. In the measurement method of adding an optical shutter to a spectroscopic white light interferometer, two steps are required for the same measurement position: one exposure is performed with the optical shutter open and the other with it closed, so that the interference spectrum and the reflection spectrum can be obtained directly respectively. This method is not suitable for online measurement. In the method of adding a polarization element and a polarization camera to a spectral white light interferometer, the polarization camera directly detects the interference spectrum signals corresponding to different phases in different regions. The reflection spectrum is indirectly obtained by calculating the interference spectrum signals of different phases. However, the hardware cost of the polarization element is high, and the usable spectral range and measurement size are limited by the wavelength range and size of the polarization element. Summary of the Invention

[0006] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a method and apparatus for simultaneous measurement of thin film surface and interface contours based on multi-band multispectral imaging. By processing the spectral image, the thickness and interface contour of the thin film sample can be obtained simultaneously, thus acquiring the surface and interface contour. The filtering function of the dichroic mirror enables the simultaneous acquisition of interference and reflection spectra, achieving the measurement of the surface and interface contour of the thin film sample under a single exposure.

[0007] To achieve the above objectives, according to one aspect of the present invention, a synchronous measurement device for thin film surface and interface profile based on multi-band multispectral imaging is provided, the measurement device comprising a spectrophotometer, a dichroic mirror, a reference mirror, an imaging lens, and a spectrometer.

[0008] During operation, the beam splitting module is used to split the received light into a first beam and a second beam, the first beam being reflected across the entire wavelength range by the thin film under test;

[0009] The light with the wavelength of the dichroic mirror transmission band in the second light beam is reflected by the reference mirror, and the rest of the light exits the measuring device; the light reflected by the reference mirror interferes with the light with the wavelength of the dichroic mirror transmission band reflected by the film in the spectrometer module to form interference light; or the light with the wavelength of the dichroic mirror reflection band in the second light beam is reflected by the reference mirror, and the rest of the light exits the measuring device; the light reflected by the reference mirror interferes with the light with the wavelength of the dichroic mirror reflection band reflected by the film in the spectrometer module to form interference light; the interference light and the light with the wavelength of the dichroic mirror transmission band reflected by the film pass through the imaging lens to reach the spectrometer.

[0010] The spectrometer simultaneously collects the spectral image of the interference light and the spectral image of the reflected light, thereby realizing the simultaneous measurement of the surface and interface profiles of the film.

[0011] Further, the measuring device further comprises a variable diaphragm, and the spectrometer module is arranged in the light exit direction of the variable diaphragm.

[0012] Further, the variable diaphragm is an aperture adjustable diaphragm, which is used to adjust the diameter of the light beam entering the spectrometer module.

[0013] Further, the spectrometer module, the dichroic mirror and the reference mirror are arranged in a first direction, and the spectrometer, the imaging lens are arranged in a second direction, and the first direction is perpendicular to the second direction; the spectrometer module comprises a coma-free cylindrical mirror, a rectangular diaphragm, a first coma-free lens, a spectrometer prism, a second coma-free lens, a third coma-free lens and a compensation sheet arranged in a first direction, and the compensation sheet, the second coma-free lens and the spectrometer prism are arranged in a second direction; the light is focused into a linear light spot after passing through the coma-free cylindrical mirror, and the linear light spot reaches the first coma-free lens after passing through the rectangular diaphragm.

[0014] Further, the size change direction of the rectangular diaphragm is parallel to the linear light spot, the length of the linear light spot is adjusted by adjusting the size of the rectangular diaphragm, and then the position of the film illuminated corresponds to the pixel coordinates of the spatial dimension of the area array camera of the spectrometer.

[0015] Further, the spectrometer prism has a 50:50 splitting ratio and is not sensitive to wavelength; and the slit of the spectrometer is located on the back focal plane of the imaging lens.

[0016] Further, the spectrometer comprises a fourth achromatic lens, a diffraction grating, a fifth achromatic lens and a plane array camera, the linear light spot from the imaging lens passes through the slit, the fourth achromatic lens and the diffraction grating to form a dispersed light beam, and the dispersed light beam passes through the fifth achromatic lens to form a two-dimensional image with spatial dimension and spectral dimension on the detection surface of the plane array camera.

[0017] Further, the slit, the back focal surface of the imaging lens and the front focal surface of the fourth achromatic lens are coincident, and the detection surface of the plane array camera and the back focal surface of the fifth achromatic lens are coincident.

[0018] Further, the light splitting module and the dichroic mirror are arranged along a first direction, the spectrometer and the imaging lens are arranged along a second direction, the reference mirror and the dichroic mirror are arranged along the second direction, and the first direction is perpendicular to the second direction; the light splitting module comprises an achromatic cylindrical mirror, a rectangular diaphragm, a first achromatic lens, a light splitting prism, a second achromatic lens and a third achromatic lens arranged along the first direction, and the second achromatic lens and the light splitting prism are arranged along the second direction; the light is focused into a linear light spot after passing through the achromatic cylindrical mirror, and the linear light spot reaches the first achromatic lens after passing through the rectangular diaphragm.

[0019] The application further provides a thin film surface and interface profile synchronous measurement method based on a sub-band multi-spectrum.

[0020] In general, compared with the prior art, the thin film surface and interface profile synchronous measurement method and device based on a sub-band multi-spectrum have the following advantages:

[0021] 1. The filtering function of the dichroic mirror enables the spectrometer to directly obtain the interference spectrum and the reflection spectrum at the same time, thereby realizing the measurement of the surface and interface profile of the sample film in a single exposure, and directly obtaining the measured sample interference spectrum and reflection spectrum without multiple exposures or reprocessing of the directly obtained light intensity, so that the measurement steps are less, the feasibility is high, the cost is low, and the method is more suitable for online measurement.

[0022] 2. The variable aperture is an aperture that can be adjusted, by changing the size of the aperture, the diameter of the collimated light beam from the collimator can be adjusted, so that the cone angle of the line spot formed by the collimated light through the achromatic cylindrical lens can be adjusted, and then the angle range through the dichroic mirror can be adjusted, and the filtering effect of the dichroic mirror for light of different angles of incidence is different, so the angle can be adjusted here so that the light of the wavelength range of the target range is filtered out.

[0023] 3. The cylindrical collimated light beam is focused into a line spot after passing through the achromatic cylindrical lens, and the line spot passes through the rectangular aperture, and by adjusting the size of the rectangular aperture, the length of the line spot can be adjusted, so that the length of the line spot focused on the film sample after passing through the optical element can be adjusted, so that the operator can determine the current measurement area.

[0024] 4. The film surface and interface profile measurement method has fewer measurement steps, can be used for online measurement of the film surface and interface profile in the fast reaction process and manufacturing situation, and has good applicability and flexibility. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structural schematic diagram of a film surface and interface profile synchronous measurement device based on a waveband-based multi-spectrum provided by the application;

[0026] Figure 2 is an optical path schematic diagram of the measurement device based on transmission waveband interference spectrum in embodiment 1;

[0027] Figure 3 is a simulation optical path diagram of the light source part to the sample end and the reference end of the measurement device based on transmission waveband interference spectrum in embodiment 1, and the interference light enters the slit;

[0028] Figure 4 is a simulation optical path diagram of the sample surface reflection light imaging to the slit of the measurement device based on transmission waveband interference spectrum in embodiment 1;

[0029] Figure 5 is Figure 1 the image obtained by the line imaging spectrometer camera of the measurement device based on transmission waveband interference spectrum in embodiment 1;

[0030] Figure 6 is an optical path schematic diagram of the measurement device based on reflection waveband interference spectrum in embodiment 2;

[0031] Figure 7 is a simulation optical path diagram of the light source part to the sample end and the reference end of the measurement device based on reflection waveband interference spectrum in embodiment 2, and the interference light enters the slit;

[0032] Figure 8 is a simulation light path diagram of sample surface reflected light imaging to a slit of the measurement device based on reflection waveband interference spectroscopy in embodiment 2;

[0033] In all the drawings, the same reference signs are used to represent the same elements or structures, wherein: 1 - wide spectrum light source, 101 - light source lamp, 102 - optical fiber, 103 - collimator, 2 - variable diaphragm, 3 - light splitting module, 301 - achromatic cylindrical mirror, 302 - rectangular diaphragm, 303 - first achromatic lens, 304 - light splitting prism, 305 - second achromatic lens, 306 - third achromatic lens, 307 - compensating plate, 4 - thin film sample, 5 - first pose adjustment table, 6 - dichroic mirror, 7 - reference mirror, 8 - second pose adjustment table, 9 - imaging lens, 10 - line imaging spectrometer, 1001 - slit, 1002 - fourth achromatic lens, 1003 - diffraction grating, 1004 - fifth achromatic lens, 1005 - area array camera, 11 - data processing module. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0035] The present application is specifically described in two embodiments, and the thin film surface and interface profile synchronous measurement device based on waveband multispectrum provided by the two embodiments both include a wide spectrum light source 1, a variable diaphragm 2, a light splitting module 3, a first pose adjustment table 5, a dichroic mirror 6, a reference mirror 7, a second pose adjustment table 8, an imaging lens 9, a spectrometer 10 and a data processing module 11.

[0036] Embodiment 1

[0037] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 , the second pose adjustment table 8, the reference mirror 7, the dichroic mirror 6, the light splitting module 3, the variable diaphragm 2 and the wide spectrum light source 1 are arranged along a first direction. The first pose adjustment table 5, the light splitting module 3, the imaging lens 9 and the line imaging spectrometer 10 are arranged along a second direction, and the first direction is perpendicular to the second direction. The data processing module 11 is connected to the line imaging spectrometer 10. Of course, in other embodiments, the line imaging spectrometer 10 can be a point spectrometer.

[0038] The light generated by the broadband light source 1 reaches the beam splitter 3 via the variable aperture 2. The beam splitter 3 splits the received light into a first beam and a second beam. The first beam is reflected across the entire wavelength range by the thin film sample mounted on the second pose adjustment stage after passing through a compensation plate. The light in the second beam with wavelengths in the transmission band of the dichroic mirror is reflected by a reference mirror mounted on the second pose adjustment stage, while the remaining light (i.e., light with wavelengths in the reflection band of the dichroic mirror) leaves the measuring device. The light reflected back from the reference mirror and the light reflected back from the thin film sample with wavelengths in the transmission band of the dichroic mirror interfere with each other in the beam splitter to form interference light. The interference light and the light reflected back from the thin film sample with wavelengths in the reflection band of the dichroic mirror pass through the imaging lens and reach the line imaging spectrometer. The simulated optical path is as follows: Figure 3 As shown, the line imaging spectrometer simultaneously acquires the spectral images of the interference light and the reflected light. The data processing module uses the spectral images of the interference light and the reflected light from the line imaging spectrometer to obtain the surface height and thickness of the thin film sample.

[0039] The broadband light source 1 includes a light source lamp 101, an optical fiber 102, and a collimator 103. The two opposite ends of the optical fiber 102 are connected to the light source lamp 101 and the collimator 103, respectively. The light source lamp 101 generates light within the transmission and reflection bands of the dichroic mirror. The optical fiber 102 transmits the light from the light source lamp 101 to the collimator 103. The collimator 103 collimates the light from the optical fiber and transmits it to the variable aperture 2. The optical fiber 102 is a small-diameter core fiber.

[0040] The variable aperture 2 is an aperture-adjustable aperture diaphragm. By changing the size of the variable aperture 2, the diameter of the parallel beam from the collimator can be adjusted, thereby adjusting the cone angle of the line spot formed by the achromatic cylindrical mirror 301 of the beam splitter, achieving the adjusted angle range after passing through the dichroic mirror. Since the filtering effect of the dichroic mirror changes for light incident at different angles, the angle can be adjusted to filter out light in the target wavelength range.

[0041] The light splitting module comprises a set of achromatic cylindrical lenses 301, a rectangular diaphragm 302, a first achromatic lens 303, a light splitting prism 304, a second achromatic lens 305, a third achromatic lens 306, and a compensating plate 307. The achromatic cylindrical lenses 301, the rectangular diaphragm 302, the first achromatic lens 303, the light splitting prism 304, and the third achromatic lens 306 are arranged along a first direction, and the compensating plate 307, the second achromatic lens 305, and the light splitting prism 304 are arranged along a second direction. The cylindrical parallel light beams emitted from the variable diaphragm 2 are focused into linear light spots by the achromatic cylindrical lenses 301, and then the linear light spots pass through the rectangular diaphragm 302 and reach the first achromatic lens 303.

[0042] In this embodiment, the size of the rectangular diaphragm 302 changes in a direction parallel to the linear light spots, and the length of the linear light spots can be adjusted by adjusting the size of the rectangular diaphragm 302, so that the length of the linear light spots focused by the optical elements on the thin film sample 4 can be adjusted, and the positions of the thin film sample 4 illuminated correspond to the pixel coordinates of the spatial dimension of the area array camera 1005 of the subsequent line imaging spectrometer, so that the operator can determine the current measurement area.

[0043] The linear light spots pass through the rectangular diaphragm 302 and the first achromatic lens, and then reach the light splitting prism 304. Preferably, the light splitting prism has a 50:50 light splitting ratio and is insensitive to wavelength. The light splitting prism splits the incident light into two beams, i.e., a first beam and a second beam. The first beam enters the sample end where the thin film sample is located, and the second beam enters the reference end where the reference mirror is located. The compensating plate 307 causes the optical path difference between the first beam and the second beam to be the optical path difference in the interference range caused by the relative distance and the thin film interference.

[0044] In the reference end, the second beam passes through the third achromatic lens 306, and the high-band light thereof passes through the dichroic mirror and reaches the reference mirror and forms a linear light spot. Preferably, the dichroic mirror has a filtering effect on the incident light at about 45°. In this embodiment, the dichroic mirror is a high-pass dichroic mirror, so that the light of high-band wavelength is transmitted to the thin film sample, and the light of low-band wavelength is reflected away from the measurement device, thereby achieving the goal that only the light of high-band wavelength interferes in the subsequent process, and only the low-band light in the reflected light of the thin film sample.

[0045] The reference mirror is placed on the second pose adjustment table 8. In this embodiment, the structure of the second pose adjustment table 8 is the same as that of the first pose adjustment table 5.

[0046] In the sample end, the first light beam passes through the second achromatic lens 305 and the compensation sheet 307 and forms a linear spot on the thin film sample 4. The light of high and low wavelength bands of the spectral light source can be transmitted through the compensation sheet 307. The thin film sample 4 is placed on the first position adjustment table 5. The first position adjustment table 5 includes a clamping frame and a manual displacement table. The clamping frame is connected to the manual displacement table. The clamping frame is used to clamp the thin film sample 4 to be measured or a reference mirror 7. The clamping frame can also adjust the plane of the clamped object to be perpendicular to the direction of the light. The movement direction of the manual displacement table is perpendicular to the length direction of the light spot focused on the surface of the thin film sample 4. The surface of the thin film sample 4 can be adjusted to be at the converging position of the linear light spot.

[0047] The high wavelength band light of the reflected light returned from the sample end and the high wavelength band light returned from the reference end interfere at the spectrometer prism 304. The high wavelength band interference light and the low wavelength band light of the reflected light returned from the sample end pass through the imaging lens and form a linear spot. Then the linear spot enters the line imaging spectrometer. The slit 1001 of the line imaging spectrometer is located on the back focal plane of the imaging lens 9. The sample is imaged on the slit plane. The simulation light path is shown in Figure 4

[0048] Please refer to Figure 2 . The line imaging spectrometer 10 includes a fourth achromatic lens 1002, a diffraction grating 103, a fifth achromatic lens 1004, and a plane array camera 1005. The linear spot from the imaging lens passes through the slit 1001, the fourth achromatic lens 1002, and the diffraction grating 1003. Then the linear spot is dispersed in the direction perpendicular to the linear spot to form a dispersed light beam. The dispersed light beam passes through the fifth achromatic lens 1004 and converges to generate a two-dimensional image with spatial and spectral dimensions on the detection surface of the plane array camera 1005. Preferably, the slit 1001, the back focal plane of the imaging lens, and the front focal plane of the fourth achromatic lens 1002 coincide. The detection surface of the plane array camera 1005 and the back focal plane of the fifth achromatic lens 1004 coincide. In addition, the signal output end of the plane array camera 1005 is connected to the data processing module.

[0049] The first achromatic lens, the second achromatic lens, the third achromatic lens 306, the imaging lens, the fourth achromatic lens 1002, and the fifth achromatic lens 1004 have high achromatic ability, including axial chromatic aberration and radial chromatic aberration.

[0050] ​In this embodiment, the specific settings are as follows: the wide spectrum light source 1 adopts a white light source with a power of 3w and a wavelength of 440-670nm, the numerical aperture of the optical fiber 102 is 0.22, and the core diameter is 600μm; the variable diaphragm 2 is an adjustable diaphragm with an aperture range of 1-24.5mm.

[0051] The collimator 103 adopts an achromatic double-cemented positive lens with a focal length of 100mm; the achromatic cylindrical mirror 301 adopts an achromatic double-cemented cylindrical lens with a focal length of 50mm; the first achromatic lens 303 adopts an achromatic double-cemented lens with a focal length of 35mm; the second achromatic lens 305 and the third achromatic lens 306 adopt the same achromatic double-cemented lens with a focal length of 80mm.

[0052] The light splitting prism 304 has a light splitting ratio of 50:50 and is coated with an anti-reflection film with a reflectivity of less than 0.5%; the compensation sheet 307 is a glass window with a thickness of 3.5mm and a material of K9L; the dichroic mirror is a long-wave pass dichroic mirror with a cutoff wavelength of 550nm, a thickness of 3.5mm and a base material of K9L; the first pose adjustment table 5 and the second pose adjustment table 8 are both supports with a double-direction angle adjustment range of ±4° around the x-axis and the z-axis and displacement devices with a single-direction moving range of 25mm along the optical axis, which are connected through connecting rods and a base.

[0053] The reference mirror 7 is coated with a high reflectivity mirror in the visible light range with a reflectivity of >88%; the imaging lens 9 is an achromatic double-cemented lens with a focal length of 152mm; the slit 1001 has a length of 10mm and a width of 20μm; the fourth achromatic lens 1002 adopts an achromatic double-cemented positive lens with a focal length of 40mm; the diffraction grating 1003 is a plane ruled diffraction grating with a blaze angle of 8°37' and a scale line of 600Lines / mm; the fifth achromatic lens 1004 is a Hastings achromatic triple-cemented lens with a focal length of 40mm; the area array camera 1005 adopts a black and white industrial camera with a 1.1" inch photosensitive chip, an image element size of 3.45μm and a pixel number of 4096×3000; the device has a scanning line length of 6.4mm.

[0054] The application also provides a thin film structure measurement method based on synchronous imaging of reflection spectrum and interference spectrum, which simultaneously measures the thickness and height of a thin film by using the thin film structure measurement device based on synchronous imaging of reflection spectrum and interference spectrum.

[0055] S1, turn on the light source, place the standard sample on the first pose adjustment table, adjust the clamping frame and the manual displacement table so that the area array camera receives the interference spectrum image, block the return light of the reference mirror, and record the spectrum image of the standard sample as calibration data.

[0056] S2, remove the standard sample, place the film sample on the first pose adjustment table, adjust the angle and the manual displacement table to make the area array camera receive the spectral image, and record the spectral image of the measured film sample.

[0057] S3, the signal of the spectral image is processed to obtain the reflectivity of the measured film sample and the optical path difference of the film sample thickness in the interference light, respectively, the reflectivity and the optical path difference are inversely solved to obtain the film thickness, and the optical path difference of the film sample interface profile height in the interference light is inversely solved to obtain the film sample interface profile height, and the interface profile is added to the corresponding position thickness to obtain the surface profile.

[0058] The spectrum obtained on the actual experimental platform is as shown in Figure 5 The right side of the figure shows that the high band light produces interference phenomenon, and the light intensity fluctuates with the size of the wavelength.

[0059] Embodiment 2

[0060] The overall structure of embodiment 2 is as shown in Figure 6 The main difference between embodiment 2 and embodiment 1 is that the reference mirror 7 and the second pose adjustment table 8 are located on one side of the dichroic mirror 6, instead of being arranged along the first direction with the dichroic mirror 6, and embodiment 2 does not set a compensator; unlike the interference between the light of the dichroic mirror transmission band and the light reflected by the film in embodiment 1, the interference between the light of the dichroic mirror reflection band and the light reflected by the film sample in embodiment 2, the interference light and the light reflected by the film sample and having a wavelength of the dichroic mirror transmission band reach the line imaging spectrometer after passing through the imaging lens, and the simulation light path is as shown in Figure 7

[0061] Specifically, compared with embodiment 1, as shown in Figure 7 The reference mirror 7 and the second pose adjustment table 8 are arranged according to the second direction. At the same time, since the glass substrate will not be transmitted through the dichroic mirror 6, the optical path difference between the first light and the second light is caused by the relative distance and the film interference in the interference range without using the compensator. The sample is imaged on the slit surface, and the simulation light path is as shown in Figure 8

[0062] The present application is based on the filtering effect of the dichroic mirror, which avoids the need for other steps, and directly obtains the interference spectrum and the reflection spectrum of the measured sample through a single frame photographing, has fewer measurement steps, and can be used for online measurement of the film surface and interface topography in the case of fast reaction process and manufacturing.

[0063] ​​Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A thin film surface and interface profile synchronous measurement device based on sub-band multi-spectrum, characterized in that: the measurement device comprises a light splitting module, a dichroic mirror, a reference mirror, an imaging lens and a spectrometer; in operation, the light splitting module is configured to split the received light into a first light beam and a second light beam, the first light beam is reflected by the thin film to be measured in full wavelength band; the light with wavelength in the transmission band of the dichroic mirror in the second light beam is reflected by the reference mirror, and the rest of the light exits the measurement device; the light reflected by the reference mirror and the light reflected by the thin film with wavelength in the transmission band of the dichroic mirror interfere with each other in the light splitting module to form interference light; the interference light and the light reflected by the thin film with wavelength in the reflection band of the dichroic mirror pass through the imaging lens and reach the spectrometer; or, the light with wavelength in the reflection band of the dichroic mirror in the second light beam is reflected by the reference mirror, and the rest of the light exits the measurement device; the light reflected by the reference mirror and the light reflected by the thin film with wavelength in the reflection band of the dichroic mirror interfere with each other in the light splitting module to form interference light; the interference light and the light reflected by the thin film with wavelength in the transmission band of the dichroic mirror pass through the imaging lens and reach the spectrometer; the spectrometer simultaneously collects the spectral images of the interference light and the reflected light, thereby realizing the simultaneous measurement of the surface and interface profile of the thin film. The measurement device further comprises a variable diaphragm, and the light splitting module is arranged in the light output direction of the variable diaphragm. The variable diaphragm is an aperture adjustable diaphragm, which is configured to adjust the diameter of the light beam entering the light splitting module. The light splitting module, the dichroic mirror and the reference mirror are arranged along a first direction, and the spectrometer and the imaging lens are arranged along a second direction, the first direction being perpendicular to the second direction; the light splitting module comprises a set of achromatic cylindrical mirrors, a rectangular diaphragm, a first achromatic lens, a light splitting prism, a second achromatic lens, a third achromatic lens and a compensating plate, the achromatic cylindrical mirrors, the rectangular diaphragm, the first achromatic lens, the light splitting prism and the third achromatic lens are arranged along the first direction, and the compensating plate, the second achromatic lens and the light splitting prism are arranged along the second direction; the light is focused into a linear light spot after passing through the achromatic cylindrical mirrors, and the linear light spot reaches the first achromatic lens after passing through the rectangular diaphragm. The size change direction of the rectangular diaphragm is parallel to the linear light spot, the length of the linear light spot is adjusted by adjusting the size of the rectangular diaphragm, and the position of the thin film illuminated corresponds to the pixel coordinates of the spatial dimension of the area array camera of the spectrometer.

2. The thin film surface interface profile simultaneous measurement device based on sub-band multi-spectrum according to claim 1, characterized in that: The light splitting prism has a 50:50 light splitting ratio and is not sensitive to wavelength; and the slit of the spectrometer is located on the back focal plane of the imaging lens.

3. The thin film surface interfacial profile simultaneous measurement device based on waveband division multispectral according to claim 2, characterized in that: ​ 4. The thin film surface and interface profile simultaneous measurement device based on sub-band multi-spectrum according to any one of claims 1-3, characterized in that: ​ 5. The thin film surface interfacial profile simultaneous measurement device based on sub-band multi-spectrum according to claim 4, characterized in that: ​ 6. The thin film surface interfacial profile simultaneous measurement device based on sub-band multi-spectrum according to claim 4, wherein: ​ 7. The thin film surface interfacial profile simultaneous measurement device based on sub-band multi-spectrum according to claim 6, wherein: The spectrometer comprises a fourth achromatic lens, a diffraction grating, a fifth achromatic lens and a plane array camera, linear light spot from the imaging lens passes through the slit, the fourth achromatic lens and the diffraction grating to form a dispersed light beam, the dispersed light beam passes through the fifth achromatic lens to converge and generate a two-dimensional image with spatial dimension and spectral dimension on the detection surface of the plane array camera.

8. The thin film surface interfacial profile simultaneous measurement device based on sub-band multi-spectrum according to claim 7, characterized in that: The rear focal plane of the slit and the imaging lens coincides with the front focal plane of the fourth achromatic lens, and the detection surface of the plane array camera coincides with the rear focal plane of the fifth achromatic lens.

9. The thin film surface interfacial profile simultaneous measurement device based on sub-band multi-spectrum according to any one of claims 1-3, characterized in that: The spectrometer, the imaging lens, the reference mirror and the dichroic mirror are arranged along a second direction, and the first direction is perpendicular to the second direction; the light splitting module comprises an achromatic cylindrical lens, a rectangular diaphragm, a first achromatic lens, a light splitting prism, a second achromatic lens and a third achromatic lens arranged along the first direction, and the second achromatic lens and the light splitting prism are arranged along the second direction; light is focused into a linear light spot after passing through the achromatic cylindrical lens, and the linear light spot reaches the first achromatic lens after passing through the rectangular diaphragm.

10. A method for simultaneous measurement of thin film surface and interface profile based on sub-band multi-spectrum, characterized in that: The measurement method simultaneously measures the surface and interface profiles of the thin film by using the thin film surface and interface profile synchronous measurement device based on the waveband division multispectrum of any one of claims 1-9.

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