WO2024000749A1

WO2024000749A1 - High-aspect-ratio micro-structured transmissive interference-microscopic nondestructive measurement apparatus and method

Info

Publication number: WO2024000749A1
Application number: PCT/CN2022/112135
Authority: WO
Inventors: 高志山; 袁群; 郭珍艳; 朱丹; 霍霄; 马剑秋; 孙一峰; 张佳乐; 范筱昕; 王书敏
Original assignee: 南京理工大学
Priority date: 2022-06-30
Filing date: 2022-08-12
Publication date: 2024-01-04
Also published as: CN115235345A

Abstract

A high-aspect-ratio micro-structured transmissive interference-microscopic nondestructive measurement apparatus and method. By using an advantage of near-infrared light being capable of penetrating through a silicon substrate, measurement can be performed by using a large numerical-aperture light beam. For the problem of the focusability of a large numerical-aperture light beam converged by a microscopic objective lens being reduced due to the large numerical-aperture light beam being modulated by a groove structure of a sample (9) under test, a microscopic objective lens exit-pupil aberration monitoring light path and an active aberration compensation system are provided; and for the problem of aberration being excessively great during detection in a reflective structure, a transmissive structure is used to reduce the aberration and improve measurement precision. The depth and width of said sample (9) are obtained by using a vertical scanning interference method. The high-aspect-ratio micro-structured transmissive interference-microscopic nondestructive measurement apparatus overcomes the difficulty of it being hard to perform nondestructive measurement on a high-aspect-ratio groove structure of a silicon-based MEMS device by using the existing measurement technology, and performs high-precision nondestructive measurement on the depth and width of a deep groove structure of said sample (9).

Description

High aspect ratio microstructure transmission interference microscopy non-destructive measurement device and measurement method

Technical field

The invention relates to the technical field of precision optical measurement engineering, and specifically relates to a high aspect ratio microstructure transmission interference microscopy non-destructive measurement device and measurement method. It measures the depth and width of the trench structure of silicon-based MEMS devices, and is particularly suitable for high-depth applications. Width ratio trench structures, usually MEMS high aspect ratio microstructures with a width of 1 to 10 μm and a depth of 10 to 300 μm, have an aspect ratio between 5:1 and 20:1.

Background technique

In the semiconductor industry, as large-scale integrated circuits and micro-nano integrated optical systems develop in a three-dimensional direction with more and more layers, it is necessary to process deep holes (TSV-through silicon vias) for electrical signal transmission leads; another Regarding various silicon-based MEMS sensors, in order to continuously improve the sensor sensitivity, it is necessary to increase the response area of the sensing structure in the sensor, making the depth of the trench-like structure larger and larger, but the line width (CD size) does not become larger, or even become smaller. These types of microstructures have the characteristics of high aspect ratio. Generally, the aspect ratio is greater than 10:1. Now the trench width of MEMS high aspect ratio microstructure is 3~10μm and the depth is 10~300μm. This kind of high aspect ratio microstructure The development of microelectromechanical systems will play a key role in driving the application of microelectromechanical system technology in many fields such as aviation, aerospace, electronics, biology, and medicine.

There are roughly two existing methods for geometric measurement of high aspect ratio microstructure devices at home and abroad: contact measurement and non-contact measurement. For contact measurement, the most commonly used instruments include scanning electron microscopes SEM and atomic force microscopes, which usually use destructive methods. The method is to cut along a line perpendicular to the direction of the trench, and use a scanning electron microscope (SEM) to detect and image the section. This detection method is destructive detection and is not conducive to process parameter optimization and process improvement in the process; non-contact measurement mainly refers to interferometric measurement technology, which is based on the principle of light wave interference. Compared with other measurement technologies, interferometric measurement Non-destructive measurements can be achieved.

In recent years, profile testing methods based on the principle of double-beam interference have emerged. Among them, white light interference devices are relatively representative. Such devices do not need to contact the sample to be tested or destroy the device structure, and can complete the three-dimensional morphology of the device without damaging it. Measurement. Since the resolution of white light is limited by the numerical aperture NA of the microscope objective, a large NA objective lens must be used to improve the resolution. However, the white light will be blocked by the high aspect ratio grooves of the sample to be measured, resulting in the large NA detection light being unable to reach the grooves. At the bottom, the imaging requirements cannot be met. Existing research reports show that the upper limit of the high aspect ratio of microstructures measured by white light interference microscopy and laser confocal microscopy is 10:1, as shown in (a) in Figure 2, for example, a trench The width is 3μm, the depth is 60μm, and the aspect ratio reaches 20:1. NA ≤ 0.025 is required to illuminate the bottom of this trench. Assuming the wavelength is 550nm, the imaging resolution exceeds 13.4μm at this time, which cannot meet the imaging requirements for the bottom of the 3μm width. . Although some people have proposed to tilt and rotate the sample to be tested so that the beam is irradiated to the bottom of the deep groove, the tilt and rotation process of the sample to be tested is very cumbersome and the entire bottom cannot be imaged at one time. Therefore, the height, depth and width of silicon-based MEMS cannot be directly measured using a white light interferometer. Than structure.

Near-infrared light can penetrate the silicon material to detect the bottom of the trench, as shown in (b) in Figure 2. However, for high aspect ratio structures, the large numerical aperture beam converged by the microscope objective will be modulated by the trench structure and reduce the beam focus. properties, resulting in aberrations, which seriously affect the imaging quality and interference fringes, and result in huge errors in the measurement results.

Chinese patent "A Micro-nano Deep Groove Structure Measuring Method and Device" (CN200710053292.5). The method is to project an infrared beam onto the surface of a silicon wafer containing a deep groove structure and analyze the reflection from each interface of the deep groove structure. The formed interference light is measured and the reflection spectrum is obtained; the equivalent medium theory is used to construct the theoretical reflection spectrum of the equivalent multi-layer film stack optical model of the deep trench structure, and the simulated annealing algorithm and the gradient-based optimization algorithm are used to calculate the theoretical reflection spectrum. The reflection spectrum is measured for fitting, and then collective characteristic parameters such as the depth and width of the groove are extracted. The method described in this patent needs to model the groove structure of the sample to be tested in advance and calculate the theoretical reflection spectrum. The measurement results of the groove depth and width are obtained by fitting with the measured spectrum. The accuracy of the measurement results is affected by Due to the influence of pre-established theoretical models, it is difficult to model samples with complex structures or unknown structures, making it difficult to ensure the accuracy of measurement results.

Chinese patent "High aspect ratio microstructure reflection type interference microscopy non-destructive measurement device" (ZL202010896309.9). The method uses a near-infrared spectrum light source with penetrating capabilities for silicon-based materials and an active compensation capability for detection light wave modulation. Linnik interference microscope is used to measure the three-dimensional morphology of high aspect ratio structures. This patent uses a reflective structure, which is mainly used to detect high aspect ratio structures with a small depth. When detecting high aspect ratio structures with a large depth, due to the limitations of its structure, the longer optical path will introduce Large aberration makes it difficult to ensure the accuracy of measurement results.

Contents of the invention

The purpose of the present invention is to provide a high aspect ratio microstructure transmission type interference microscopy non-destructive measurement device and measurement method to solve the problem that the existing interference microscopy non-destructive measurement method cannot measure the depth and width of MEMS high aspect ratio trench structures. Problems in making measurements and reflection interference microscopy measurement devices still have problems with excessive aberrations during measurements.

The technical solution to achieve the purpose of the present invention is: a high aspect ratio microstructure transmission interference microscopy non-destructive measurement device, including a near-infrared short-coherence light source, a Kohler illumination system, a sample to be measured, a second microscope objective, a first center Following mirror group, deformable mirror, second plane reflector, third cubic beam splitting prism, fourth cubic beam splitting prism, tube mirror, first infrared detector, pupil mirror, monochromatic filter, second infrared detector, The third plane reflector, the fourth plane reflector, the second relay mirror group, the third microscope objective lens, the compensation plate, the fifth plane reflector, and the piezoelectric ceramic PZT; the fifth plane reflector is arranged on the piezoelectric ceramic PZT superior.

The sample to be tested, the second microscope objective lens, the first relay lens group, the second plane reflector, and the deformation mirror constitute the test optical path. The third plane reflector, the fourth plane reflector, the second relay lens group, and the third The microscope objective lens and the compensation plate constitute the reference optical path.

The Kohler illumination system includes a first condenser, a first cubic beam splitter prism, a second condenser, a third condenser, a second cubic beam splitter, a first plane reflector, a first microscopic objective, a fourth condenser, and a fifth condenser. The fifth cubic beam splitting prism, the fifth plane reflector, and the fourth microscope objective lens.

The piezoelectric ceramic PZT and the first infrared detector are connected to form a synchronous scanning and acquisition system; the deformable mirror and the second infrared detector cooperate to form an aberration detection optical path and an active compensation system.

The near-infrared short coherent light source emits a multi-field beam, which is condensed by the first condenser to the first cubic beam splitter and then divided into test light and reference light; the test light passes through the second condenser and the third condenser and then reaches the second cubic beam splitter. The second cubic beam splitter reflects to the first plane mirror, and then is reflected by the first plane mirror and then transmitted through the second cubic beam splitter to the first microscope objective. It illuminates the sample to be measured and then penetrates the sample to be measured, and then in sequence After passing through the second microscope objective lens, the first relay lens group and the deformable mirror, it reaches the second plane mirror, is reflected by the second plane mirror to the third cubic beam splitting prism, and is transmitted to the fourth cubic beam splitting prism through the third cubic beam splitting prism. Prism, the fourth cubic beam splitting prism divides the light into two parts. After one part of the light passes through the pupil mirror and the monochromatic filter, the pupil of the second microscopic objective lens is imaged on the second infrared detector; the other part of the light passes through the tube mirror. Finally, the sample to be measured is imaged on the first infrared detector; the reference light passes through the fifth condenser and the fourth condenser in sequence and then enters the fifth cubic beam splitting prism, and is reflected by the fifth cubic beam splitting prism to the fifth beam on the piezoelectric ceramic PZT. The plane reflector, after being reflected by the fifth plane mirror, passes through the fifth cubic beam splitting prism, the fourth microscope objective lens, the illumination compensation plate, the third microscope objective lens, the second relay lens group, and the fourth plane reflector in sequence. It is reflected by the fourth plane reflector to the third plane reflector, and then reflected to the third cubic beam splitting prism through the third plane reflector. The third cubic beam splitting prism reflects it to the fourth cubic beam splitting prism. The fourth cubic beam splitting prism will The light is divided into two parts. One part of the light interferes with the test light on the first infrared detector after passing through the tube mirror; the other part of the light interferes with the test light on the second infrared detector after passing through the pupil mirror and monochromatic filter. , construct an optical path for monitoring the exit pupil aberration of the microscope objective, use piezoelectric ceramic PZT to drive the movement of the fifth plane mirror, and use the second infrared detector to collect 4 phase-shifting interference patterns, and calculate the pupil of the second microscope objective Aberration; feedback the pupil aberration of the second microscope objective lens to the shape of the deformable mirror, thereby compensating the pupil aberration, and constructing an active aberration compensation system; using vertical scanning interference method to drive the fifth plane through piezoelectric ceramic PZT The reflector moves, and the first infrared detector simultaneously receives the interference fringe patterns on the surface of the sample to be measured at different depths. At the same time, the piezoelectric ceramic PZT is used to control the movement of the sample to be measured, and the interference fringe patterns at different positions on the surface of the sample to be measured are obtained. Finally, using The vertical scanning interference algorithm processes the interference pattern to obtain the depth and width of the groove of the sample to be tested.

A transmission interference microscopy non-destructive measurement method for high aspect ratio microstructures. The steps are as follows:

Step 1. Place the sample to be measured on the confocal plane of the first microscopic objective lens and the second microscopic objective lens, and obtain an image with aberrations and a low-contrast interference fringe pattern on the first infrared detector;

Step 2. Use the second infrared detector to monitor the pupil aberration of the second microscope objective, use the piezoelectric ceramic PZT to drive the fifth plane mirror to move, and use the second infrared detector to collect 4 phase-shifting interference patterns, and calculate Obtain pupil aberration.

Step 3. The deformable mirror adjusts its shape according to the monitored pupil aberration, and the compensation results are observed on the second infrared detector. After compensation, a clear image and a high-contrast interference fringe pattern are observed on the first infrared detector.

Step 4: Use the vertical scanning interference method to drive the fifth plane reflector through the piezoelectric ceramic PZT. The first infrared detector simultaneously collects the interference fringe pattern, and uses the vertical scanning interference algorithm to process the interference pattern.

Step 5: Finally obtain the depth and width of the groove structure of the sample to be tested.

Compared with the prior art, the significant advantages of the present invention are:

(1) For the sample to be tested with a silicon-based MEMS high aspect ratio trench structure, a near-infrared short coherent light source is used to penetrate the deep trench to the bottom. A large NA microscope objective can be used, which solves the problem that the large NA beam cannot detect the high aspect ratio trench. Problems with the bottom of the trough structure.

(2) In order to solve the problem that the large NA beam converged by the microscope objective lens is modulated by the groove structure of the sample to be tested and reduces the focus of the beam, a microscopic objective lens exit pupil aberration monitoring optical path and an aberration active compensation system are constructed to monitor the changes caused by the sample to be tested. The aberration generated by the deep groove structure is fed back to the deformable mirror to actively compensate for the aberration, improving imaging quality and interference fringe contrast, and ensuring measurement accuracy.

(3) In order to solve the problem of excessive aberration when measuring the object to be measured by the reflective micro-interferometry device, a transmissive structure is adopted. Compared with the reflective structure, the optical path is reduced by half, thereby reducing the aberration. , higher measurement accuracy.

Description of drawings

Figure 1 is a schematic diagram of a transmission interference microscopy non-destructive measurement device for high aspect ratio microstructures.

Figure 2 is a schematic diagram of converging a beam to detect the bottom of the trench of the sample to be tested. (a) in Figure 2 shows the use of white light to detect the bottom blocked by the side wall; (b) in Figure 2 shows the use of near-infrared light to penetrate the side wall to detect the bottom. , but the beam focusability deteriorates; (c) in Figure 2 shows that the beam can be converged to the bottom of the groove after compensation using a deformable mirror.

Figure 3 is a functional block diagram of pupil aberration monitoring and active compensation.

Figure 4 shows the interference pattern collected by the infrared detector. (a) in Figure 4 is the interference pattern before compensation by the deformable mirror; (b) in Figure 4 is the interference pattern after compensation by the deformable mirror.

Figure 5 shows the measurement results of the high aspect ratio trench structure.

Detailed ways

In order to make the above objects, features and advantages of the present invention more obvious and understandable, the specific implementation modes of the present invention will be described in detail below with reference to the accompanying drawings.

With reference to Figure 1, a high aspect ratio microstructure transmission interference microscopy non-destructive measurement device includes a near-infrared short coherent light source 1, a Kohler illumination system, a sample to be measured 9, a second microscopic objective lens 10, and a first relay lens group 11. Deformable mirror 13, second plane mirror 12, third cubic beam splitting prism 14, fourth cubic beam splitting prism 15, tube mirror 16, first infrared detector 17, pupil mirror 18, monochromatic filter 19, The second infrared detector 20, the third plane mirror 21, the fourth plane mirror 22, the second relay lens group 23, the third microscope objective lens 24, the compensation plate 25, the fifth plane mirror 28, and piezoelectric ceramics PZT29; the fifth plane reflector 28 is provided on the piezoelectric ceramic PZT29.

The sample to be tested 9, the second microscope objective lens 10, the first relay lens group 11, the second plane mirror 12, and the deformation mirror 13 constitute the test optical path. The third plane mirror 21, the fourth plane mirror 22, the second The relay lens group 23, the third microscope objective lens 24, and the compensation plate 25 constitute a reference optical path.

The Kohler illumination system includes a first condenser 2, a first cubic beam splitter prism 3, a second condenser 4, a third condenser 5, a second cubic beam splitter 7, a first plane reflector 6, a first microscopic objective lens 8, Four condenser lenses 30 , a fifth condenser lens 31 , a fifth cubic beam splitter prism 27 , a fifth plane reflector 29 , and a fourth microscopic objective lens 26 .

The piezoelectric ceramic PZT29 and the first infrared detector 17 are connected to form a synchronous scanning and acquisition system; the deformable mirror 13 and the second infrared detector 20 cooperate to form an aberration detection optical path and an active compensation system.

The near-infrared short coherent light source 1 emits a multi-field light beam, which is condensed to the first cubic beam splitter 3 through the first condenser 2 and then divided into test light and reference light; the test light passes through the second condenser 4 and the third condenser 5 to the second The cubic beam splitter 7 is reflected by the second cubic beam splitter 7 to the first plane reflector 6, and then reflected by the first plane reflector 6 and then transmitted to the first microscope objective lens 8 by the second cubic beam splitter 7, and is then illuminated. After measuring the sample 9, it penetrates the sample 9 to be measured, and then passes through the second microscope objective lens 10, the first relay lens group 11, and the deformation mirror 13 in turn to reach the second plane reflector 12, and is reflected by the second plane reflector 12 to The third cubic beam splitting prism 14 is transmitted to the fourth cubic beam splitting prism 15 through the third cubic beam splitting prism 14. The fourth cubic beam splitting prism 15 divides the light into two parts, and part of the light passes through the pupil mirror 18 and the monochromatic filter 19 Finally, the pupil of the second microscope objective lens 10 is imaged on the second infrared detector 20; another part of the light passes through the tube lens 16 and the sample 9 to be measured is imaged on the first infrared detector 17; the reference light passes through the fifth condenser in sequence 31. The fourth condenser 30 then enters the fifth cubic beam splitting prism 27 and is reflected by the fifth cubic beam splitting prism 27 to the fifth plane reflector 28 on the piezoelectric ceramic PZT 29. After being reflected by the fifth plane reflector 28, it is sequentially reflected by the fifth plane mirror 28. After the five cubic beam splitting prism 27, the fourth microscopic objective lens 26, the illumination compensation plate 25, the third microscopic objective lens 24, the second relay lens group 23 and the fourth plane reflector 22, it is reflected by the fourth plane reflector 22 to The third plane reflection mirror 21 then reflects it to the third cubic beam splitting prism 14. The third cubic beam splitting prism 14 reflects it to the fourth cubic beam splitting prism 15. The fourth cubic beam splitting prism 15 splits the light. It is two parts. One part of the light interferes with the test light on the first infrared detector 17 after passing through the tube mirror 16; the other part of the light passes through the pupil mirror 18 and the monochromatic filter 19 and interferes with the test light on the second infrared detector 20. Interference occurs on the microscope objective lens, an optical path for monitoring the exit pupil aberration of the microscope objective is constructed, the piezoelectric ceramic PZT29 is used to drive the fifth plane reflector 28 to move, and the second infrared detector 20 is used to collect 4 phase-shifting interference patterns, and the second display is calculated and obtained. The pupil aberration of the micro objective lens 10; feedback the pupil aberration of the second micro objective lens 10 to the shape of the deformable mirror 13, thereby compensating the pupil aberration, and constructing an active aberration compensation system; using the vertical scanning interference method to pass The piezoelectric ceramic PZT29 drives the fifth plane reflector 28 to move, and simultaneously receives the interference fringe patterns of the surface of the sample 9 at different depths on the first infrared detector 17. At the same time, the piezoelectric ceramic PZT29 is used to control the movement of the sample 9 to be measured, and obtain the sample 9 to be measured. The interference fringe patterns at different positions on the surface of sample 9 are measured, and finally the vertical scanning interference algorithm is used to process the interference pattern to obtain the depth and width of the grooves of sample 9 to be measured.

The test optical path is completely consistent with the reference optical path, and the position of the sample to be tested 9 in the test optical path corresponds to the position of the compensation plate 25 in the reference optical path.

The near-infrared short coherent light source 1 is located on the front focal plane of the first condenser 2, the first condenser 2 and the second condenser 4 are confocal, the second condenser 4 and the third condenser 5 are confocal, the first microscopic objective lens 8 and The third condenser lens 5 is confocal; the first condenser lens 2 and the fifth condenser lens 31 are confocal, the fifth condenser lens 31 and the fourth condenser lens 30 are confocal, and the fourth condenser lens 30 and the fourth microscope objective lens 26 are confocal.

The sample to be tested 9 is on the focal plane of the first microscopic objective lens 8 and the second microscopic objective lens 10, and the pupil plane of the second microscopic objective lens 10 is conjugated with the deformable mirror 13 with respect to the first relay lens group 11, The first relay lens group 11 includes two identical and confocal condenser lenses, with an aperture placed at the focus position to block stray light.

The first infrared detector 17 , the confocal surface of the first relay lens group 11 and the sample to be measured 9 are conjugate.

The pupil of the second microscopic objective lens 10 is imaged on the second infrared detector 20 through the first relay lens group 11, the deformation mirror 13, the pupil lens 18 and the monochromatic filter 19. The second microscopic objective lens The pupil of 10, the deformable mirror 13 and the second infrared detector 20 are conjugate, and the central wavelength of the monochromatic filter 19 is the same as the central wavelength of the near-infrared short coherent light source 1; the piezoelectric ceramic PZT29 is used to drive the fifth plane reflector 28 And use the second infrared detector 20 to collect 4 phase-shifted interference patterns, and calculate the pupil aberration; according to the obtained pupil aberration, the deformable mirror 13 is actively adjusted to compensate for the aberration, so that the large numerical aperture beam converges to the target. The bottom of the groove of the sample 9 is measured and penetrates the sample 9 to be tested. Compared with the reflective structure test light path passing through the pupil surface twice, the transmission structure test light only passes through the second microscope objective 10 once after penetrating the sample. Pupil aberration is reduced by half, which shows that the transmissive structure can solve the aberration caused by the larger aspect ratio structure.

The test light penetrating the silicon substrate of the sample will additionally produce transmitted wave aberration, which is offset by using the compensation plate 25 in the reference optical path.

Further, the incident light and the outgoing light of the deformable mirror 13 are perpendicular, and the outgoing light irradiates the second plane reflecting mirror 12 frontally and is reflected by the second plane reflecting mirror 12. The direction of the reflected light beam is changed to be consistent with the incident light of the deforming mirror 13. .

Further, the outgoing light of the fourth plane reflecting mirror 22 is perpendicular to the incident light. After the outgoing light of the fourth plane reflecting mirror 22 irradiates the third plane reflecting mirror 21 frontally, it is reflected by the third plane reflecting mirror 21 and the direction of the reflected light beam is changed. to be consistent with the incident light of the fourth plane reflecting mirror 22 .

Combined with Figure 2, the white light is blocked by the groove structure of the sample 8 as shown in Figure 2 (a). The near-infrared light penetrates the sample 8 but is modulated by the groove structure and reduces the focus as shown in Figure 2. As shown in (b), after using the deformable mirror 12 to compensate for aberration, the near-infrared large numerical aperture beam can be converged to the bottom of the groove, as shown in (c) of Figure 2.

Combining Figure 3, Figure 4 and Figure 5, a transmission interference microscopy non-destructive measurement method for high aspect ratio microstructures, the steps are as follows:

Step 1. Place the surface of the sample 9 to be measured on the confocal plane of the first microscopic objective lens 8 and the second microscopic objective lens 10, and obtain an image with aberration and low contrast on the first infrared detector 17. The interference fringe pattern is shown in (a) in Figure 4.

Step 2: Use the second infrared detector 20 to monitor the pupil aberration of the microscope objective, use the piezoelectric ceramic PZT29 to drive the fifth plane reflector 28 and use the second infrared detector 20 to collect 4 phase-shifting interference patterns, and calculate the light Pupil aberration.

Step 3: Adjust the shape of the deformable mirror 13 according to the monitored pupil aberration, and observe the compensation result on the second infrared detector 20. After compensation, a clear image and high-contrast interference fringes are observed on the first infrared detector 17. Figure, as shown in (b) in Figure 4.

Step 4: Use the vertical scanning interference method to drive the fifth plane reflector 28 through the piezoelectric ceramic PZT29. The first infrared detector 17 simultaneously collects the interference fringe pattern, and uses the vertical scanning interference algorithm to process the interference pattern.

Step 5: Finally obtain the depth and width measurement results of the groove structure of sample 9, as shown in Figure 5.

Claims

A high aspect ratio microstructure transmission type interference microscopy non-destructive measurement device, which is characterized by: including a near-infrared short-coherence light source (1), a Kohler illumination system, a sample to be measured (9), a second microscope objective lens (10), The first relay mirror group (11), the deformable mirror (13), the second plane reflector (12), the third cubic beam splitting prism (14), the fourth cubic beam splitting prism (15), the tube mirror (16), the third An infrared detector (17), pupil mirror (18), monochromatic filter (19), second infrared detector (20), third plane reflector (21), fourth plane reflector (22) , the second relay lens group (23), the third microscope objective lens (24), the compensation plate (25), the fifth plane reflector (28), the piezoelectric ceramic PZT (29); the fifth plane reflector (28 ) is set on the piezoelectric ceramic PZT (29);

The sample to be tested (9), the second microscope objective lens (10), the first relay lens group (11), the second plane reflector (12), and the deformation mirror (13) constitute the test optical path, and the third plane reflector (12) 21), the fourth plane reflector (22), the second relay lens group (23), the third microscope objective lens (24), and the compensation plate (25) constitute the reference optical path;

The Kohler lighting system includes a first condenser (2), a first cubic beam splitter prism (3), a second condenser (4), a third condenser (5), a second cubic beam splitter prism (7), and a first plane reflector. (6), the first microscopic objective lens (8), the fourth condenser lens (30), the fifth condenser lens (31), the fifth cubic beam splitter prism (27), the fifth plane reflector (29), the fourth microscopic objective lens (26);

The piezoelectric ceramic PZT (29) and the first infrared detector (17) are connected to form a synchronous scanning acquisition system; the deformable mirror (13) and the second infrared detector (20) cooperate to form an aberration detection optical path and an active compensation system;

The near-infrared short coherent light source (1) emits a multi-field light beam, which is condensed to the first cubic beam splitter (3) through the first condenser (2) and then divided into test light and reference light; the test light passes through the second condenser (4), After the third condenser (5), it reaches the second cubic beam splitter (7), and is reflected by the second cubic beam splitter (7) to the first plane reflector (6), and then reflected by the first plane reflector (6). After the second cubic beam splitter (7) transmits to the first microscope objective lens (8), it illuminates the sample to be measured (9), penetrates the sample to be measured (9), and then passes through the second microscope objective lens (10), A relay lens group (11) and a deformable mirror (13) turn to reach the second plane reflector (12), and are reflected by the second plane reflector (12) to the third cubic beam splitting prism (14). The prism (14) is transmitted to the fourth cubic dichroic prism (15). The fourth cubic dichroic prism (15) divides the light into two parts. A part of the light passes through the pupil mirror (18) and the monochromatic filter (19). The pupil of the second microscope objective lens (10) is imaged on the second infrared detector (20); the other part of the light is imaged on the first infrared detector (17) after passing through the tube lens (16). ; The reference light passes through the fifth condenser (31) and the fourth condenser (30) in sequence, then enters the fifth cubic beam splitter prism (27), and is reflected by the fifth cubic beam splitter prism (27) to the piezoelectric ceramic PZT (29). The fifth plane reflector (28), after being reflected by the fifth plane reflector (28), is sequentially passed through the fifth cubic beam splitting prism (27), the fourth microscope objective lens (26), the illumination compensation plate (25), and the third display After the micro objective lens (24), the second relay lens group (23), and the fourth plane mirror (22), it is reflected by the fourth plane mirror (22) to the third plane mirror (21), and then through the third plane mirror (21). The plane reflector (21) reflects to the third cubic beam splitting prism (14), the third cubic beam splitting prism (14) reflects it to the fourth cubic beam splitting prism (15), and the fourth cubic beam splitting prism (15) divides the light into Two parts, one part of the light interferes with the test light after passing through the tube mirror (16) on the first infrared detector (17); the other part of the light passes through the pupil mirror (18) and the monochromatic filter (19) and interferes with the test light. Interference occurs on the second infrared detector (20), the piezoelectric ceramic PZT (29) is used to drive the fifth plane reflector (28) to move, and the second infrared detector (20) is used to collect 4 phase-shifting interference patterns, The pupil aberration of the second microscopic objective lens (10) is calculated and obtained; the pupil aberration of the second microscopic objective lens (10) is fed back to the shape of the deformable mirror (13), thereby compensating the pupil aberration; using vertical The scanning interference method drives the fifth plane reflector (28) to move through the piezoelectric ceramic PZT (29), and simultaneously receives the interference fringe patterns of the surface of the sample (9) at different depths at different depths on the first infrared detector (17), and simultaneously uses The piezoelectric ceramic PZT (29) controls the movement of the sample to be tested (9) to obtain interference fringe patterns at different positions on the surface of the sample to be tested (9). Finally, a vertical scanning interference algorithm is used to process the interference pattern to obtain the grooves of the sample to be tested (9). The depth and width of the groove.
A high aspect ratio microstructure transmission type interference microscopy non-destructive measurement device according to claim 1, characterized in that: the test light path is completely consistent with the reference light path, wherein the position of the sample to be tested (9) in the test light path is consistent with that of the reference light path. The position of the compensation plate (25) in the reference optical path corresponds to that.
A high aspect ratio microstructure transmission type interference microscopy non-destructive measurement device according to claim 2, characterized in that: the near-infrared short coherent light source (1) is located on the front focal plane of the first condenser (2), The first condenser lens (2) and the second condenser lens (4) are confocal, the second condenser lens (4) and the third condenser lens (5) are confocal, and the first microscopic objective lens (8) and the third condenser lens (5) are confocal; The first condenser lens (2) and the fifth condenser lens (31) are confocal, the fifth condenser lens (31) and the fourth condenser lens (30) are confocal, and the fourth condenser lens (30) and the fourth microscope objective lens (26) are confocal.
A high aspect ratio microstructure transmission type interference microscopy non-destructive measurement device according to claim 3, characterized in that: the sample to be measured (9) is between the first microscopic objective lens (8) and the second microscopic objective lens. (10), the pupil surface of the second microscopic objective lens (10) and the deformable mirror (13) are conjugate with respect to the first relay lens group (11). The first relay lens group (11) includes two An identical and confocal condenser, with an aperture placed at the focal point to block stray light.
A high aspect ratio microstructure transmission interference microscopy non-destructive measurement device according to claim 4, characterized in that: the confocal of the first infrared detector (17) and the first relay lens group (11) The surface is conjugated with the sample to be measured (9).
A high aspect ratio microstructure transmission type interference microscopy non-destructive measurement device according to claim 5, characterized in that: the pupil of the second microscopic objective lens (10) passes through the first relay lens group (11) , the deformable mirror (13), the pupil mirror (18) and the monochromatic filter (19) are imaged on the second infrared detector (20), the pupil of the second microscope objective (10), the deformable mirror (13) ) is conjugated with the second infrared detector (20), and the central wavelength of the monochromatic filter (19) is the same as the central wavelength of the near-infrared short-coherence light source (1); the piezoelectric ceramic PZT (29) is used to drive the fifth plane The reflector (28) uses the second infrared detector (20) to collect 4 phase-shifted interference patterns, and calculates the pupil aberration; according to the obtained pupil aberration, the deformable mirror (13) is actively adjusted to compensate for the aberration. The large numerical aperture beam is converged to the bottom of the groove of the sample to be tested (9) and penetrates the sample to be tested (9). Compared with the reflective structure test light path passing through the pupil surface twice, the transmission structure is used to test the light penetration of the sample. After passing through the second microscope objective lens (10) only once, the pupil aberration is reduced by half, which shows that the transmissive structure can solve the aberration caused by the larger aspect ratio structure.
A high aspect ratio microstructure transmission interference microscopy non-destructive measurement device according to claim 1, characterized in that when the test light penetrates the silicon substrate of the sample (9) to be tested, additional transmission wave aberration will be generated. A compensation plate (25) is used in the reference optical path for cancellation.
A high aspect ratio microstructure transmission type interference microscopy non-destructive measurement device according to claim 1, characterized in that: the incident light and the outgoing light of the deformable mirror (13) are perpendicular, and the outgoing light irradiates the second plane reflector (13) frontally. 12), and is reflected by the second plane reflecting mirror (12), and the direction of the reflected light beam is changed to be consistent with the incident light of the deformable mirror (13).
A high aspect ratio microstructure transmission type interference microscopy non-destructive measurement device according to claim 1, characterized in that: the outgoing light of the fourth plane reflector (22) is perpendicular to the incident light, and the fourth plane reflector (22) ), the emitted light irradiates the third plane reflector (21) frontally, and is reflected by the third plane reflector (21). The direction of the reflected light beam is changed to be consistent with the incident light of the fourth plane reflector (22).
A transmission interference microscopy non-destructive measurement method for high aspect ratio microstructures, which is characterized by: the steps are as follows:

Step 1. Place the sample to be measured (9) on the confocal plane of the first microscopic objective lens (8) and the second microscopic objective lens (10), and obtain an image with an image on the first infrared detector (17). Poor images and low-contrast interference fringe patterns;

Step 2: Use the second infrared detector (20) to monitor the pupil aberration of the second microscope objective lens (10), use the piezoelectric ceramic PZT (29) to drive the fifth plane mirror (28) to move, and use the second The infrared detector (20) collects four phase-shifted interference patterns and calculates the pupil aberration;

Step 3. Adjust the shape of the deformable mirror (13) according to the monitored pupil aberration, observe the compensation result on the second infrared detector (20), and observe a clear image on the first infrared detector (17) after compensation and high-contrast interference fringe patterns;

Step 4. Use the vertical scanning interference method to drive the fifth plane reflector (28) through the piezoelectric ceramic PZT (29). The first infrared detector (17) synchronously collects the interference fringe pattern, and uses the vertical scanning interference algorithm to process the interference pattern;

Step 5: Obtain the depth and width of the groove structure of the sample (9) to be tested.