Device and method for measuring deep trench structure parameters based on near-infrared spectral scattering

Abstract

This invention belongs to the field of optical thin film measurement, and specifically discloses a device and method for measuring the parameters of deep trench structures based on near-infrared spectral scattering. It includes an illumination optical path and a measurement optical path, wherein: the illumination optical path is used for auxiliary illumination to locate the position of the sample to be measured; the measurement optical path is used to acquire the reflected light intensity spectrum of the sample to be measured; wherein, the beam emitted by the infrared light source passes sequentially through a first condenser lens, a circular aperture, a first beam splitter, a polarizer, a rectangular aperture, and a second condenser lens before illuminating the structure to be measured; the beam returning from the structure to be measured returns along the same path to the first beam splitter, and then sequentially passes through a second beam splitter, a third condenser lens, a reflecting mirror, and a fourth condenser lens before converging onto a spectrometer; the circular aperture and the second condenser lens cooperate to control the incident angle of the measurement optical path, and the rectangular aperture is used to control the azimuth angle of the measurement optical path. This invention can achieve accurate measurement of the structural parameters of deep trench samples at the micrometer level.

Description

Technical Field

[0001] This invention belongs to the field of optical thin film measurement, and more specifically, relates to a device and method for measuring the parameters of deep trench structures based on near-infrared spectral scattering. Background Technology

[0002] With the continuous improvement of silicon-based MEMS process technology and application levels, while the surface film thickness of semiconductor devices can be measured, a demand has also arisen for the measurement of deep trench structures. High aspect ratio trench structures, due to their narrow and vertical air gaps and large specific surface area, can significantly improve charge storage capacity, increase interdigital capacitance and sensor sensitivity, and have wide applications in comb-shaped microelectrode arrays, supercapacitors, accelerometers, gyroscopes, gratings, and micro / nano resonators. To improve the manufacturing quality of MEMS trenches and ensure device yield, it is necessary to measure and analyze the three-dimensional feature dimensions of MEMS with high aspect ratios. Among these, depth, width, and sidewall angle have the greatest impact on MEMS device performance and are also the most critical common measurement techniques that need to be addressed in the process. Currently, the main method for measuring the three-dimensional feature dimensions of MEMS microtrenches is to destructively cut open the cross-section of the sample and then scan it with an electron microscope. This method suffers from problems such as sample damage, complex preparation, and time-consuming measurement. Therefore, a new, rapid, and non-destructive measurement method is urgently needed.

[0003] For the measurement needs of nanoscale shallow trench structures similar to the characteristics of MEMS deep trench structures, OCD (Optical Critical Dimension) measurement method is commonly used. OCD utilizes the high sensitivity of ellipsometric spectroscopy to nanoscale structural parameters, and it is generally very sensitive to changes in sub-nanometer structural dimensions, thus finding wide application in integrated circuit process monitoring. However, for periodic high aspect ratio trench structures with linewidths ranging from nanometer to micrometer scales and aspect ratios greater than 10:1, the ellipsometric spectra obtained by OCD measurement suffer from severe depolarization due to factors such as half-bandwidth and incident angle (NA) characteristics, resulting in the loss of accurate structural parameter information and posing a significant challenge to accurate ellipsometric spectral modeling. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a device and method for measuring the parameters of deep trench structures based on near-infrared spectral scattering, the purpose of which is to improve the accuracy of measuring the three-dimensional feature dimensions of high aspect ratio trench structures.

[0005] To achieve the above objectives, according to one aspect of the present invention, a device for measuring the parameters of a deep trench structure based on near-infrared spectral scattering is proposed, comprising an illumination optical path and a measurement optical path, wherein:

[0006] The illumination optical path is used for auxiliary illumination to locate the position of the sample to be tested;

[0007] The measurement optical path is used to acquire the reflected light intensity spectrum of the sample under test. The beam emitted from the infrared light source passes sequentially through a first condenser, a circular aperture, a first beam splitter, a polarizer, a rectangular aperture, and a second condenser before illuminating the structure under test. The beam returning from the structure under test returns to the first beam splitter and then sequentially passes through a second beam splitter, a third condenser, a reflecting mirror, and a fourth condenser before converging onto the spectrometer. The circular aperture and the second condenser work together to control the incident angle of the measurement optical path, and the rectangular aperture controls the azimuth angle of the measurement optical path.

[0008] As a further preferred embodiment, in the illumination optical path, the light beam emitted by the LED illumination source passes sequentially through the fifth condenser lens, the second beam splitter, the first beam splitter, the polarizer, the rectangular aperture, and the second condenser lens to form an illumination area on the sample stage; then the light beam carrying the sample position information returns to the second beam splitter along the original path, and passes sequentially through the third condenser lens, the reflector, and the relay lens to converge into the CCD camera.

[0009] As a further preferred embodiment, the first and second beam splitters are Polka-Dot beam splitters.

[0010] As a further preferred embodiment, the infrared light source is a xenon lamp light source, and the wavelength of the infrared beam emitted by the infrared light source is 1.0μm to 1.7μm.

[0011] As a further preferred embodiment, the focal length ratio of the first condenser lens and the second condenser lens is 1:1.

[0012] As a further preferred embodiment, the reflector is a pinhole reflector.

[0013] According to another aspect of the present invention, a method for measuring deep trench structures is provided, which is implemented by the aforementioned deep trench structure measuring device based on near-infrared spectral scattering, and includes the following steps:

[0014] The reflected light intensity spectrum I of a black sample with a reflectivity of 0 was measured using a deep trench structure parameter measuring device. b (λ), and reflectance spectrum R r The reflected light intensity spectrum of the standard aspect ratio structural sample (λ) r (λ);

[0015] Adjust the polarizer angle and measure the reflected light intensity spectrum I of the sample under p-polarized light. m-p (λ), and its measured reflected light intensity spectrum I under s-polarized light m-s (λ), and thus the reflectance spectrum of the sample to be tested is obtained;

[0016] The structural parameters of the sample under test are constructed using the rigorous coupled-wave method to obtain a theoretical reflectance spectrum library. The measured reflectance spectrum of the sample under test is then fitted with the theoretical reflectance spectrum library to obtain the structural parameters of the sample under test.

[0017] As a further preferred option, when measuring the reflected light intensity spectrum, the incident angle of the measurement optical path is controlled within 0.5 degrees by using a circular aperture and a second condenser lens.

[0018] As a further preferred option, when measuring the reflected light intensity spectrum, the azimuth angle of the measuring optical path is controlled within 15 degrees by using a rectangular aperture.

[0019] As a further preferred option, the reflectance spectrum R of the sample to be tested is obtained according to the following formula. meas :

[0020]

[0021] Among them, T r T is the integration time corresponding to the measurement of a standard aspect ratio structural sample. m-p T is the integration time corresponding to the measurement of the p-polarization state of the sample under test. m-s The integral time is the time corresponding to the measurement of the polarization state of the sample under test.

[0022] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0023] 1. This invention achieves control over the incident angle and azimuth angle of the measurement system by designing circular and rectangular apertures in the measurement optical path, thereby reducing the influence of the incident angle and azimuth angle on the reflectivity of the sample. It can realize the measurement of deep trench samples with a depth-to-width ratio of more than 10:1 at the micrometer level, thus obtaining accurate characteristics such as depth, width, and sidewall angle of the deep trench structure.

[0024] 2. The device of the present invention is non-contact and non-destructive. The measuring device is simple and easy to operate, and can quickly and accurately obtain the parameters of key dimensions. At the same time, the device has a compact structure, which is more in line with the miniaturization and miniaturization requirements of modern measuring devices.

[0025] 3. The present invention also includes an imaging unit, which, by setting up an illumination source, an industrial camera and optical components, can image and observe the sample to be measured, thereby helping to find the local area to be measured before measurement, so as to improve measurement efficiency and measurement accuracy.

[0026] 4. The beam splitter used in this invention is a Polka-Dot beam splitter. Compared with standard dielectric film beam splitters, the Polka-Dot beam splitter offers unique advantages, maintaining consistent reflectivity / transmittance over a wider spectral range. The infrared light source is a xenon lamp, meeting the wavelength requirement of 1.0μm to 1.7μm. This wavelength band of infrared light has high penetrability and is also compatible with the wavelength range of infrared spectrometers. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a deep trench structure parameter measurement device based on near-infrared spectral scattering, according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the conical beam of the measuring device of the present invention incident on the sample surface;

[0029] Figure 3 This is a schematic diagram of the beam incident angle distribution of the measuring device according to an embodiment of the present invention;

[0030] Figure 4 This is a comparison chart of reflectance curves at different incident angles and azimuth angles according to an embodiment of the present invention;

[0031] Figure 5 This is an array diagram of various linewidths of the sample measured under a microscope according to an embodiment of the present invention.

[0032] Figure 6 (a)-(c) are schematic diagrams showing the specific dimensions of the 2µm linewidth sample measured under a scanning electron microscope in the embodiments of the present invention.

[0033] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-infrared light source, 2-first condenser lens, 3-circular aperture, 4-first beam splitter, 5-polarized light, 6-rectangular aperture, 7-second condenser lens, 8-second beam splitter, 9-third condenser lens, 10-reflector, 11-fourth condenser lens, 12-infrared spectrometer, 13-LED illumination source, 14-fifth condenser lens, 15-relay lens, 16-CCD camera. Detailed Implementation

[0034] 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 and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0035] This invention provides a device for measuring the parameters of deep trench structures based on near-infrared spectral scattering, such as... Figure 1As shown, it includes an illumination optical path and a measurement optical path, wherein:

[0036] In the measurement optical path, the light beam emitted by the infrared light source 1 passes sequentially through the first condenser lens 2, the circular aperture 3, the first beam splitter 4, the polarizer 5, the rectangular aperture 6, and the second condenser lens 7, illuminating the sample to be tested. The parallel light passing through the first condenser lens 2 forms a 45° angle with the first beam splitter 4. The light beam that hits the sample and returns to the receiver then passes sequentially through the second condenser lens 7, the rectangular aperture 6, the polarizer 5, the first beam splitter 4, the second beam splitter 8, the third condenser lens 9, the reflector 10, and the fourth condenser lens 11, converging at the receiving end of the infrared spectrometer 12, and then connecting to the computer.

[0037] Specifically, the incident angle of the entire measurement system is controlled by the circular aperture 3 and the second condenser lens 7, while the azimuth angle of the system is controlled by the rectangular aperture 6.

[0038] In the illumination path, the light beam emitted by the LED illumination source 13 passes sequentially through the fifth condenser lens 14, the second beam splitter 8, the first beam splitter 4, the polarizer 5, the rectangular aperture 6, and the second condenser lens 7, forming an illumination area on the sample stage. The parallel light passing through the fifth condenser lens 14 forms a 45° angle with the second beam splitter 8. The light beam carrying sample position information then passes sequentially through the second condenser lens 7, the rectangular aperture 6, the polarizer 5, the first beam splitter 4, the second beam splitter 8, and the third condenser lens 9, before being deflected by the reflector 10 and then through the repeater 15, finally converging into the CCD camera 16. The reflected light from the illumination path hitting the sample stage forms a 45° angle with the reflected light from the pinhole reflector.

[0039] Specifically, the illumination optical path in this device mainly serves as auxiliary illumination to help quickly locate the position to be measured on the sample during the measurement process; the function of the fifth condenser lens 14 is to concentrate the energy of the illumination source onto the sample to be measured, thereby improving the final image quality; the reflected light from the illumination optical path is reflected by the reflector 10 and finally hits the detector of the CCD camera 16.

[0040] Preferably, the deep trench structure studied in this invention has a linewidth ranging from a few micrometers to tens of micrometers and an aspect ratio of over 10:1, meaning the trench depth is typically from tens to hundreds of micrometers. Therefore, the device of this invention uses a wavelength of 1.0 μm to 1.7 μm. This wavelength is chosen partly to utilize the high penetrability of infrared light in this band and partly to match the wavelength range of the infrared spectrometer. The infrared light source 1 uses a xenon lamp, typically with a wavelength range of 300 nm to 2500 nm, meeting the required wavelength. Because the measurement sample of this invention, such as... Figure 5 As shown, Figure 5The measurement sample consists of arrays of samples with varying linewidths, such as 2-2, which is composed of many single-slot arrays with a slot width and spacing of 2µm. According to measurements under a microscope, the width of this region is approximately 220µm. To ensure sufficient energy intensity, a 200µm infrared optical fiber was selected; simultaneously, the focal length ratio of the first condenser lens 2 and the second condenser lens 7 was approximately 1:1 to ensure that the light spot hitting the sample was around 200µm.

[0041] Preferably, the first beam splitter 4 is a Polka-Dot beam splitter. Compared with standard dielectric film beam splitters, Polka-Dot beam splitters offer unique advantages by maintaining consistent reflectance / transmittance over a wider spectral range. The second beam splitter 8 is also a Polka-Dot beam splitter. Since this type of beam splitter has different transmittance, it needs to be used in conjunction with the first beam splitter to meet the requirements of the device of this invention.

[0042] Preferably, the reflector 10 is a pinhole reflector. The characteristic of this pinhole reflector structure is that light can pass through the small hole in the middle, while the entire surface except for the small hole is reflective. Then the third condenser 9 focuses the reflected light, improving the energy utilization rate, and then through the transmission hole in the pinhole reflector, and finally through the fourth condenser 11 to be focused into the spectrometer.

[0043] The measurement of deep trench structures using the above-mentioned measuring device includes the following steps:

[0044] S1. Measure the reflected light intensity spectrum of the standard sample, the reflected light intensity spectrum of the black sample, and the reflected light intensity spectrum of the sample to be tested, and then calculate the reflectance spectrum of the sample to be tested.

[0045] Specifically, when measuring the reflected light intensity spectrum, the infrared beam is first collimated, then converted into linearly polarized light by polarizer 5, and then controlled by the azimuth angle of the system by the rectangular aperture 6. The incident angle of the system is then controlled by the circular aperture 3 and the second condenser lens 7. With the assistance of the illumination optical path, the area to be measured is found and measured. The infrared beam is located in the near-infrared band with a wavelength of 1.0 to 1.7 μm. After being reflected by each surface of the sample, the incident beam is finally focused into the spectrometer by the fourth condenser lens 11 to obtain the light intensity signal of the sample, i.e., the reflected light intensity spectrum.

[0046] Furthermore, the control system's incident angle and azimuth angle aim to approach 0 degrees for the entire system. However, in reality, instruments cannot achieve absolutely zero incident angle and azimuth angle. Therefore, methods such as... Figure 6 Optical simulation was performed on a slot with a theoretical slot width and slot spacing of 5µm. Through optical simulation, as shown... Figure 4As shown, comparing the approximation of reflectance curves obtained at different incident angles and azimuth angles reveals that the reflectance curve obtained at an incident angle of 0.5 degrees essentially coincides with the reflectance curve obtained at an incident angle of 0 degrees, and the reflectance curve obtained at an azimuth angle of 15 degrees essentially coincides with the reflectance curve obtained at an azimuth angle of 0 degrees. Therefore, during measurement, it is necessary to control the incident angle and azimuth angle of the entire system to achieve the measurement of the sample under test. The incident angle should be controlled within 0.5 degrees, and the azimuth angle within 15 degrees. Within these ranges, the incident angle and azimuth angle have almost no impact on the obtained theoretical spectral reflectance curve.

[0047] Step S1 specifically includes:

[0048] (1) Measure the reflected light intensity spectrum of the standard sample. Since the reflected light intensity value of the standard sample is the largest under the same integration time, first measure the reflected light spectrum of the standard sample to determine the integration time of the spectrometer. First, place the standard sample on the sample stage. Initially, a small integration time can be set. Then, adjust the Z-axis displacement stage and observe the change in spectral intensity. When the peak value of the spectrum reaches the maximum value, stop rotating the Z-axis displacement stage. Then, modify the integration time of the spectrometer until the peak intensity of the spectrum reaches about 60,000. Set the average number of times of the spectrometer. Generally, it is set to 20-40 times. In this way, the random error of the measured spectrum is small. Finally, save the standard sample spectral data.

[0049] (2) Measure the reflected light intensity spectrum of the black sample, remove the standard sample, and place the black sample with a reflectance of 0 on the sample stage. At this time, there is no need to adjust the position of the sample stage. The spectrometer uses the same integration time and averaging number as the standard sample and saves the spectral data of the black sample.

[0050] (3) Measure the reflected light intensity spectrum of the sample to be tested, remove the black sample, place the sample to be tested on the sample stage, adjust the position of the XY axis displacement stage so that the measurement spot is aligned with the test area of ​​the deep groove sample, adjust the Z axis displacement stage so that the peak value of the reflected spectrum of the sample to be tested reaches the maximum, use the same integration time and averaging number as the standard sample for the spectrometer, and save the reflected spectrum data of the sample to be tested.

[0051] The intensity spectrum of reflected light from a black sample with zero reflectivity is measured, and this intensity is denoted as I. b (λ), the measured reflectance spectrum is R r The reflected light intensity spectrum of a standard aspect ratio structural sample with (λ) is denoted as I. r (λ); Adjust the polarizer angle and measure the intensity spectrum of the reflected light from the high aspect ratio structure sample with an unknown reflectance spectrum under p-polarized light. Record this intensity as I. m-p (λ); Further, the polarizer angle is adjusted, and the intensity spectrum of the reflected light from the high aspect ratio structure sample (same as the p-polarized light measurement sample) with an unknown reflectance spectrum is measured under s-polarized light. This intensity is denoted as I.m-s (λ).

[0052] There is a certain relationship between the correction light intensity and the integration time; the light intensity changes with the integration time. Therefore, the integration time must be taken into account in the reflection polarization measurement system. In this process, T... r I is the integration time corresponding to the measurement of a standard aspect ratio sample. m-p (λ) is the integration time corresponding to the measurement of the standard sample in the p-polarization state, and similarly, I m-s (λ) represents the integration time corresponding to the measurement of the polarization state of the standard sample s.

[0053] Then the reflectance spectrum R of the sample to be tested meas for:

[0054]

[0055] S2. Perform optical simulation on the deep groove sample and build a library within the possible range of sample parameters. That is, obtain the theoretical reflectivity spectrum of the sample under test through modeling and simulation. Then, use machine learning to match the measured reflectivity spectrum with the simulated theoretical reflectivity spectrum. Through continuous iteration, narrow the parameter range and gradually approach the true value of the key dimension parameters of the sample.

[0056] Specifically, the relationship between reflectivity and the structural parameters of the sample under test is a transcendental function, which cannot be expressed explicitly as a function. Therefore, a functional relationship is established between light intensity and wavelength, and the linewidth and tilt angle in the structure under test are considered as parameters in the function. The relationship between reflectivity and wavelength λ is as follows:

[0057] R meas =R meas (λ,CD unknown SWA unknown )

[0058] In the formula, CD unknown SWA represents the linewidth of the sample to be tested. unknown The tilt angle of the sample to be tested.

[0059] Furthermore, by continuously assigning linewidth CD and tilt angle values ​​SWA to the measuring device, a reflectance spectrum (i.e., a function of reflectance corresponding to wavelength) can be obtained; given a linewidth / tilt angle sequence: [CD / SWA] ​​= [CD1 / SWA1, CD2 / SWA2, CD3 / SWA3...CD] n / SWA n The corresponding reflectance spectrum sequence is obtained, which is called the reflectance spectrum family R. cale =[R1(λ1),R2(λ2),R3(λ3),...R n (λ n )).

[0060] Then, based on the reflectance spectrum R of the sample to be tested meas The structural parameters of the sample under test are obtained by fitting a reflectance spectrum family. Specifically, to ensure sufficient measurement accuracy, a "fitting" method is used, that is, finding a reflectance spectrum in the reflectance spectrum family that best fits the measured reflectance spectrum across the entire wavelength range. The best fit condition is that the difference between the theoretical reflectance spectrum and the measured reflectance spectrum is minimized at various points, that is, the mean square error is minimized. In a spectral scattering system, this characteristic is represented by MSE.

[0061]

[0062] Where m is the number of wavelength points, R calc and R meas These refer to the reflectance spectra under theoretical and measured conditions, respectively.

[0063] Ideally, R calc It will be able to perfectly fit R meas At this point, MSE equals 0; however, the theoretical model idealizes the high aspect ratio structure, so in reality R calc It cannot perfectly fit R meas In other words, the MSE cannot be 0. Therefore, by finding the minimum value of the MSE function, we can obtain the best-fitting R. meas R calc At this point, it is approximately assumed that R is... calc The corresponding structural linewidth and tilt angle [CD / SWA] ​​are the linewidth and tilt angle of the high aspect ratio structure to be measured.

[0064] This invention can measure the film thickness on the surface of semiconductor devices and also measure the key dimensions of deep trench structure samples, extracting the three-dimensional feature dimensions of deep trenches, such as depth, width, and sidewall angles. It is a common key measurement technology that needs to be solved in the process.

[0065] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for measuring deep trench structures, characterized in that, The measurement of deep trench structure parameters is achieved using a device based on near-infrared spectral scattering; the device includes an illumination optical path and a measurement optical path, wherein: The illumination optical path is used for auxiliary illumination to locate the position of the sample to be tested; The measurement optical path is used to obtain the reflected light intensity spectrum of the sample to be tested; wherein, the light beam emitted by the infrared light source (1) passes through the first condenser (2), the circular aperture (3), the first beam splitter (4), the polarizer (5), the rectangular aperture (6), and the second condenser (7) in sequence, and then illuminates the structure to be tested; the light beam returning from the structure to be tested returns to the first beam splitter (4) along the original path, and then passes through the second beam splitter (8), the third condenser (9), the reflector (10), and the fourth condenser (11) in sequence, and converges to the infrared spectrometer (12); the circular aperture (3) and the second condenser (7) cooperate to control the incident angle of the measurement optical path, and the rectangular aperture (6) is used to control the azimuth angle of the measurement optical path; The measurement method for deep trench structures includes the following steps: The reflected light intensity spectrum of a black sample with a reflectivity of 0 was measured using a deep trench structure parameter measuring device. and reflectance spectrum is Reflected light intensity spectrum of standard aspect ratio structural sample ; Adjust the polarizer angle and measure the reflected light intensity spectrum of the sample under p-polarized light. And its measured reflected light intensity spectrum under s-polarized light. Thus, the reflectance spectrum of the sample under test is obtained; The structural parameters of the sample under test are constructed using the rigorous coupled-wave method to obtain a theoretical reflectance spectrum library. The measured reflectance spectrum of the sample under test is then fitted with the theoretical reflectance spectrum library to obtain the structural parameters of the sample under test.

2. The method for measuring deep trench structures as described in claim 1, characterized in that, In the illumination optical path, the light beam emitted by the LED illumination source (13) passes through the fifth condenser (14), the second beam splitter (8), the first beam splitter (4), the polarizer (5), the rectangular aperture (6), and the second condenser (7) in sequence, and forms an illumination area on the sample stage; then the light beam carrying the sample position information returns to the second beam splitter (8) along the original path, and passes through the third condenser (9), the reflector (10), and the relay mirror (15) in sequence, and converges into the CCD camera (16).

3. The method for measuring deep trench structures as described in claim 2, characterized in that, The first beam splitter (4) and the second beam splitter (8) are Polka-Dot beam splitters.

4. The method for measuring deep trench structures as described in claim 1, characterized in that, The infrared light source (1) is a xenon lamp light source, and the infrared light beam emitted by the infrared light source (1) has a wavelength of 1.0μm to 1.7μm.

5. The method for measuring deep trench structures as described in claim 1, characterized in that, The focal length ratio of the first condenser lens (2) and the second condenser lens (7) is 1:

1.

6. The method for measuring deep trench structures as described in any one of claims 1-5, characterized in that, The reflector (10) is a pinhole reflector.

7. The method for measuring deep trench structures as described in claim 1, characterized in that, When measuring the intensity spectrum of reflected light, the incident angle of the measurement optical path is controlled within 0.5 degrees by using a circular aperture (3) and a second condenser (7).

8. The method for measuring deep trench structures as described in claim 1, characterized in that, When measuring the intensity spectrum of reflected light, the azimuth angle of the measuring optical path is controlled within 15 degrees by using a rectangular aperture (6).

9. The method for measuring deep trench structures as described in claim 1, characterized in that, The reflectance spectrum of the sample to be tested is obtained according to the following formula. R meas : in, The integral time is the time required to measure a standard aspect ratio structural sample. The integral time corresponding to the measurement of the p-polarization state of the sample under test. The integral time is the time corresponding to the measurement of the polarization state of the sample under test.

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